freebsd/contrib/cvs/doc/cvs.texinfo

\input texinfo  @c -*-texinfo-*-
@comment cvs.texinfo,v 1.6 1995/10/12 23:39:26 kfogel Exp
@comment Documentation for CVS.
@comment Copyright (C) 1992, 1993 Signum Support AB
@comment Copyright (C) 1993 Free Software Foundation, Inc.

@comment This file is part of the CVS distribution.

@comment CVS is free software; you can redistribute it and/or modify
@comment it under the terms of the GNU General Public License as published by
@comment the Free Software Foundation; either version 1, or (at your option)
@comment any later version.

@comment CVS is distributed in the hope that it will be useful,
@comment but WITHOUT ANY WARRANTY; without even the implied warranty of
@comment MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
@comment GNU General Public License for more details.

@comment You should have received a copy of the GNU General Public License
@comment along with CVS; see the file COPYING.  If not, write to
@comment the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.

@afourpaper
@setfilename cvs.info
@include CVSvn.texi
@settitle CVS---Concurrent Versions System
@setchapternewpage odd

@c -- TODO list:
@c -- Fix all lines that match "^@c -- "
@c -- Document how CVS finds the binaries it executes.
@c Things to include in the index:
@c Finding RCS binaries
@c Path to RCS binaries
@c RCS, how CVS finds them
@c s/RCS/diff/
@c -- More on binary files

@ifinfo
Copyright @copyright{} 1992, 1993 Signum Support AB
Copyright @copyright{} 1993, 1994 Free Software Foundation, Inc.

Permission is granted to make and distribute verbatim copies of
this manual provided the copyright notice and this permission notice
are preserved on all copies.

@ignore
Permission is granted to process this file through Tex and print the
results, provided the printed document carries copying permission
notice identical to this one except for the removal of this paragraph
(this paragraph not being relevant to the printed manual).

@end ignore
Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided also that the
section entitled ``GNU General Public License'' is included exactly as
in the original, and provided that the entire resulting derived work is
distributed under the terms of a permission notice identical to this one.

Permission is granted to copy and distribute translations of this manual
into another language, under the above conditions for modified versions,
except that the section entitled ``GNU General Public License'' and
this permission notice may be included in translations approved by the
Free Software Foundation instead of in the original English.
@end ifinfo

@comment The titlepage section does not appear in the Info file.
@titlepage
@sp 4
@comment The title is printed in a large font.
@center @titlefont{Version Management}
@sp
@center @titlefont{with}
@sp
@center @titlefont{CVS}
@sp 2
@center for @sc{cvs} @value{CVSVN}
@comment -release-
@sp 3
@center Per Cederqvist et al

@comment  The following two commands start the copyright page
@comment  for the printed manual.  This will not appear in the Info file.
@page
@vskip 0pt plus 1filll
Copyright @copyright{} 1992, 1993 Signum Support AB

Permission is granted to make and distribute verbatim copies of
this manual provided the copyright notice and this permission notice
are preserved on all copies.

Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided also that the
section entitled ``GNU General Public License'' is included exactly as
in the original, and provided that the entire resulting derived work is
distributed under the terms of a permission notice identical to this one.

Permission is granted to copy and distribute translations of this manual
into another language, under the above conditions for modified versions,
except that the section entitled ``GNU General Public License'' and
this permission notice may be included in translations approved by the
Free Software Foundation instead of in the original English.
@end titlepage

@comment ================================================================
@comment                   The real text starts here
@comment ================================================================

@ifinfo
@c ---------------------------------------------------------------------
@node    Top
@top 
@c Note: there is a space after that @top command.
@c The texinfo-format-buffer Emacs function and
@c the makeinfo shell command disagree on what arguments
@c @top takes; @top followed by a single space is
@c something they can both cope with.

This info manual describes how to use and administer
@sc{cvs} version @value{CVSVN}.
@end ifinfo

@menu
* Preface::                     About this manual
* What is CVS?::                What is CVS?
* Basic concepts::              Basic concepts of revision management
* A sample session::            A tour of basic CVS usage
* Repository::                  Where all your sources are stored
* Starting a new project::      Starting a project with CVS
* Multiple developers::         How CVS helps a group of developers
* Branches::                    Parallel development explained
* Merging::                     How to move changes between branches
* Recursive behavior::          CVS descends directories
* Adding files::                Adding files to a module
* Removing files::              Removing files from a module
* Tracking sources::            Tracking third-party sources
* Moving files::                Moving and renaming files
* Moving directories::          Moving and renaming directories
* History browsing::            Viewing the history of files in various ways
* Keyword substitution::        CVS can include the revision inside the file
* Binary files::                CVS can handle binary files
* Revision management::         Policy questions for revision management
* Invoking CVS::                Reference manual for CVS commands
* Administrative files::        Reference manual for the Administrative files
* Environment variables::       All environment variables which affect CVS
* Troubleshooting::             Some tips when nothing works
* Copying::                     GNU GENERAL PUBLIC LICENSE
* Index::                       Index
@end menu

@c ---------------------------------------------------------------------
@node Preface
@unnumbered About this manual
@cindex Preface
@cindex About this manual

Up to this point, one of the weakest parts of @sc{cvs}
has been the documentation.  @sc{cvs} is a complex
program.  Previous versions of the manual were written
in the manual page format, which is not really well
suited for such a complex program.

When writing this manual, I had several goals in mind:

@itemize @bullet
@item
No knowledge of @sc{rcs} should be necessary.

@item
No previous knowledge of revision control software
should be necessary.  All terms, such as @dfn{revision
numbers}, @dfn{revision trees} and @dfn{merging} are
explained as they are introduced.

@item
The manual should concentrate on the things @sc{cvs} users
want to do, instead of what the @sc{cvs} commands can do.
The first part of this manual leads you through things
you might want to do while doing development, and
introduces the relevant @sc{cvs} commands as they are
needed.

@item
Information should be easy to find.  In the reference
manual in the appendices almost all information about
every @sc{cvs} command is gathered together.  There is also
an extensive index, and a lot of cross references.
@end itemize

@cindex Signum Support
@cindex Support, getting CVS support
This manual was contributed by Signum Support AB in
Sweden.  Signum is yet another in the growing list of
companies that support free software.  You are free to
copy both this manual and the @sc{cvs} program.
@xref{Copying}, for the details.  Signum Support offers
@c -- Check this reference! It has been bogus in the past.
support contracts and binary distribution for many
programs, such as @sc{cvs}, @sc{gnu} Emacs, the
@sc{gnu} C compiler and others.  Write to us for
more information.

@example
Signum Support AB
Box 2044
S-580 02  Linkoping
Sweden

Email: info@@signum.se
Phone: +46 (0)13 - 21 46 00
Fax:   +46 (0)13 - 21 47 00
@end example

Another company selling support for @sc{cvs} is Cyclic
Software, web: @code{http://www.cyclic.com/}, email:
@code{info@@cyclic.com}.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@menu
* Checklist::                   
* Credits::                     
* BUGS::                        
@end menu

@node Checklist
@unnumberedsec Checklist for the impatient reader

@sc{cvs} is a complex system.  You will need to read
the manual to be able to use all of its capabilities.
There are dangers that can easily be avoided if you
know about them, and this manual tries to warn you
about them.  This checklist is intended to help you
avoid the dangers without reading the entire manual.
If you intend to read the entire manual you can skip
this table.

@table @asis
@item Binary files
@sc{cvs} can handle binary files, but
you must have @sc{rcs} release 5.5 or later and
a release of @sc{gnu} diff that supports the @samp{-a}
flag (release 1.15 and later are OK).  You must also
configure both @sc{rcs} and @sc{cvs} to handle binary
files when you install them.

Keword substitution can be a source of trouble with
binary files. @xref{Keyword substitution}, for
solutions.

@item The @code{admin} command
Uncareful use of the @code{admin} command can cause
@sc{cvs} to cease working.  @xref{admin}, before trying
to use it.
@end table

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Credits
@unnumberedsec Credits

@cindex Contributors (manual)
@cindex Credits (manual)
Roland Pesch, Cygnus Support <@t{pesch@@cygnus.com}>
wrote the manual pages which were distributed with
@sc{cvs} 1.3.  Appendix A and B contain much text that
was extracted from them.  He also read an early draft
of this manual and contributed many ideas and
corrections.

The mailing-list @code{info-cvs} is sometimes
informative. I have included information from postings
made by the following persons:
David G. Grubbs <@t{dgg@@think.com}>.

Some text has been extracted from the man pages for
@sc{rcs}.

The @sc{cvs} @sc{faq} (@pxref{What is CVS?}) by David
G. Grubbs has been used as a check-list to make sure
that this manual is as complete as possible.  (This
manual does however not include all of the material in
the @sc{faq}).  The @sc{faq} contains a lot of useful
information.

In addition, the following persons have helped by
telling me about mistakes I've made:
Roxanne Brunskill <@t{rbrunski@@datap.ca}>,
Kathy Dyer <@t{dyer@@phoenix.ocf.llnl.gov}>,
Karl Pingle <@t{pingle@@acuson.com}>,
Thomas A Peterson <@t{tap@@src.honeywell.com}>,
Inge Wallin <@t{ingwa@@signum.se}>,
Dirk Koschuetzki <@t{koschuet@@fmi.uni-passau.de}>
and Michael Brown <@t{brown@@wi.extrel.com}>.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node BUGS
@unnumberedsec BUGS

@cindex Bugs, known in this manual
@cindex Known bugs in this manual
This manual is known to have room for improvement.
Here is a list of known deficiencies:

@itemize @bullet
@item
In the examples, the output from @sc{cvs} is sometimes
displayed, sometimes not.

@item
The input that you are supposed to type in the examples
should have a different font than the output from the
computer.

@item
This manual should be clearer about what file
permissions you should set up in the repository, and
about setuid/setgid.

@item
Some of the chapters are not yet complete.  They are
noted by comments in the @file{cvs.texinfo} file.

@item
@cindex Reporting bugs (manual)
@cindex Bugs, reporting (manual)
@cindex Errors, reporting (manual)
This list is not complete.  If you notice any error,
omission, or something that is unclear, please send
mail to @t{bug-cvs@@prep.ai.mit.edu}.
@end itemize

I hope that you will find this manual useful, despite
the above-mentioned shortcomings.

@flushright

Linkoping, October 1993
Per Cederqvist
@end flushright

@c ---------------------------------------------------------------------
@node What is CVS?
@chapter What is CVS?
@cindex What is CVS?
@cindex Introduction to CVS
@cindex CVS, introduction to

@sc{cvs} is a version control system.  Using it, you can
record the history of your source files.

@c -- ///
@c -- ///Those who cannot remember the past are condemned to repeat it.
@c -- ///               -- George Santayana
@c -- //////

@c -- Insert history  quote here!
For example, bugs sometimes creep in when
software is modified, and you might not detect the bug
until a long time after you make the modification.
With @sc{cvs}, you can easily retrieve old versions to see
exactly which change caused the bug.  This can
sometimes be a big help.

You could of course save every version of every file
you have ever created.  This would
however waste an enormous amount of disk space.  @sc{cvs}
stores all the versions of a file in a single file in a
clever way that only stores the differences between
versions.

@sc{cvs} also helps you if you are part of a group of people working
on the same project.  It is all too easy to overwrite
each others' changes unless you are extremely careful.
Some editors, like @sc{gnu} Emacs, try to make sure that
the same file is never modified by two people at the
same time.  Unfortunately, if someone is using another
editor, that safeguard will not work.  @sc{cvs} solves this problem
by insulating the different developers from each other.  Every
developer works in his own directory, and @sc{cvs} merges
the work when each developer is done.

@cindex History of CVS
@cindex CVS, history of
@cindex Credits (CVS program)
@cindex Contributors (CVS program)
@sc{cvs} started out as a bunch of shell scripts written by
Dick Grune, posted to @code{comp.sources.unix} in the volume 6
release of December, 1986.  While no actual code from
these shell scripts is present in the current version
of @sc{cvs} much of the @sc{cvs} conflict resolution algorithms
come from them.

In April, 1989, Brian Berliner designed and coded @sc{cvs}.
Jeff Polk later helped Brian with the design of the @sc{cvs}
module and vendor branch support.

@cindex Source, getting CVS source
You can get @sc{cvs} via anonymous ftp from a number of
sites, for instance @t{prep.ai.mit.edu} in
@file{pub/gnu}.

@cindex Mailing list
@cindex List, mailing list
There is a mailing list for @sc{cvs} where bug reports
can be sent, questions can be asked, an FAQ is posted,
and discussion about future enhancements to @sc{cvs}
take place.  To submit a message to the list, write to
<@t{info-cvs@@prep.ai.mit.edu}>.  To subscribe or
unsubscribe, write to
<@t{info-cvs-request@@prep.ai.mit.edu}>. Please be
specific about your email address.


@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@unnumberedsec CVS is not@dots{}

@sc{cvs} can do a lot of things for you, but it does
not try to be everything for everyone.

@table @asis
@item @sc{cvs} is not a build system.

Though the structure of your repository and modules
file interact with your build system
(e.g. @file{Makefile}s), they are essentially
independent.

@sc{cvs} does not dictate how you build anything.  It
merely stores files for retrieval in a tree structure
you devise.

@sc{cvs} does not dictate how to use disk space in the
checked out working directories.  If you write your
@file{Makefile}s or scripts in every directory so they
have to know the relative positions of everything else,
you wind up requiring the entire repository to be
checked out.  That's simply bad planning.

If you modularize your work, and construct a build
system that will share files (via links, mounts,
@code{VPATH} in @file{Makefile}s, etc.), you can
arrange your disk usage however you like.

But you have to remember that @emph{any} such system is
a lot of work to construct and maintain.  @sc{cvs} does
not address the issues involved.  You must use your
brain and a collection of other tools to provide a
build scheme to match your plans.

Of course, you should place the tools created to
support such a build system (scripts, @file{Makefile}s,
etc) under @sc{cvs}.

@item @sc{cvs} is not a substitute for management.

Your managers and project leaders are expected to talk
to you frequently enough to make certain you are aware
of schedules, merge points, branch names and release
dates.  If they don't, @sc{cvs} can't help.

@sc{cvs} is an instrument for making sources dance to
your tune.  But you are the piper and the composer.  No
instrument plays itself or writes its own music.

@item @sc{cvs} is not a substitute for developer communication.

When faced with conflicts within a single file, most
developers manage to resolve them without too much
effort.  But a more general definition of ``conflict''
includes problems too difficult to solve without
communication between developers.

@sc{cvs} cannot determine when simultaneous changes
within a single file, or across a whole collection of
files, will logically conflict with one another.  Its
concept of a @dfn{conflict} is purely textual, arising
when two changes to the same base file are near enough
to spook the merge (i.e. @code{diff3}) command.

@sc{cvs} does not claim to help at all in figuring out
non-textual or distributed conflicts in program logic.

For example: Say you change the arguments to function
@code{X} defined in file @file{A}.  At the same time,
someone edits file @file{B}, adding new calls to
function @code{X} using the old arguments.  You are
outside the realm of @sc{cvs}'s competence.

Acquire the habit of reading specs and talking to your
peers.


@item @sc{cvs} is not a configuration management system.

@sc{cvs} is a source control system.  The phrase
``configuration management'' is a marketing term, not
an industry-recognized set of functions.

A true ``configuration management system'' would contain
elements of the following:

@itemize @bullet
@item Source control.
@item Dependency tracking.
@item Build systems (i.e. What to build and how to find
things during a build.  What is shared?  What is local?)
@item Bug tracking.
@item Automated Testing procedures.
@item Release Engineering documentation and procedures.
@item Tape Construction.
@item Customer Installation.
@item A way for users to run different versions of the same
software on the same host at the same time.
@end itemize

@sc{cvs} provides only the first.
@end table

This section is taken from release 2.3 of the @sc{cvs}
@sc{faq}.

@c ---------------------------------------------------------------------
@node Basic concepts
@chapter Basic concepts
@cindex Modules (intro)
@cindex Repository (intro)

@sc{cvs} stores all files in a centralized
@dfn{repository}: a directory (such as
@file{/usr/local/cvsroot} or
@file{user@@remotehost:/usr/local/cvsroot}) which is
populated with a hierarchy of files and directories.
(@pxref{Remote repositories} for information about
keeping the repository on a remote machine.)

Normally, you never access any of the files in the
repository directly.  Instead, you use @sc{cvs}
commands to get your own copy of the files, and then
work on that copy.  When you've finished a set of
changes, you check (or @dfn{commit}) them back into the
repository.

The files in the repository are organized in
@dfn{modules}.  Each module is made up of one or more
files, and can include files from several directories.
A typical usage is to define one module per project.

@menu
* Revision numbers::            The meaning of a revision number
* Versions revisions releases::  Terminology used in this manual
@end menu

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Revision numbers
@section Revision numbers
@cindex Revision numbers
@cindex Revision tree
@cindex Linear development
@cindex Number, revision-
@cindex Decimal revision number
@cindex Main trunk (intro)
@cindex Branch number
@cindex Number, branch

Each version of a file has a unique @dfn{revision
number}.  Revision numbers look like @samp{1.1},
@samp{1.2}, @samp{1.3.2.2} or even @samp{1.3.2.2.4.5}.
A revision number always has an even number of
period-separated decimal integers.  By default revision
1.1 is the first revision of a file.  Each successive
revision is given a new number by increasing the
rightmost number by one.  The following figure displays
a few revisions, with newer revisions to the right.

@example
       +-----+    +-----+    +-----+    +-----+    +-----+
       ! 1.1 !----! 1.2 !----! 1.3 !----! 1.4 !----! 1.5 !
       +-----+    +-----+    +-----+    +-----+    +-----+
@end example

@sc{cvs} is not limited to linear development.  The
@dfn{revision tree} can be split into @dfn{branches},
where each branch is a self-maintained line of
development.  Changes made on one branch can easily be
moved back to the main trunk.  

Each branch has a @dfn{branch number}, consisting of an
odd number of period-separated decimal integers.  The
branch number is created by appending an integer to the
revision number where the corresponding branch forked
off.  Having branch numbers allows more than one branch
to be forked off from a certain revision.

@need 3500
All revisions on a branch have revision numbers formed
by appending an ordinal number to the branch number.
The following figure illustrates branching with an
example.

@example
@group
                                                     +-------------+
                          Branch 1.2.2.3.2 ->        ! 1.2.2.3.2.1 !
                                                   / +-------------+
                                                  /
                                                 /
                 +---------+    +---------+    +---------+    +---------+
Branch 1.2.2 -> _! 1.2.2.1 !----! 1.2.2.2 !----! 1.2.2.3 !----! 1.2.2.4 !
               / +---------+    +---------+    +---------+    +---------+
              /
             /
+-----+    +-----+    +-----+    +-----+    +-----+
! 1.1 !----! 1.2 !----! 1.3 !----! 1.4 !----! 1.5 !      <- The main trunk
+-----+    +-----+    +-----+    +-----+    +-----+
                !
                !
                !   +---------+    +---------+    +---------+
Branch 1.2.4 -> +---! 1.2.4.1 !----! 1.2.4.2 !----! 1.2.4.3 !
                    +---------+    +---------+    +---------+

@end group
@end example

@c --   However, at least for me the figure is not enough.  I suggest more
@c --   text to accompany it.  "A picture is worth a thousand words", so you
@c --   have to make sure the reader notices the couple of hundred words
@c --   *you* had in mind more than the others!

@c --   Why an even number of segments?  This section implies that this is
@c --   how the main trunk is distinguished from branch roots, but you never
@c --   explicitly say that this is the purpose of the [by itself rather
@c --   surprising] restriction to an even number of segments.

The exact details of how the branch number is
constructed is not something you normally need to be
concerned about, but here is how it works: When
@sc{cvs} creates a branch number it picks the first
unused even integer, starting with 2.  So when you want
to create a branch from revision 6.4 it will be
numbered 6.4.2.  All branch numbers ending in a zero
(such as 6.4.0) are used internally by @sc{cvs}
(@pxref{Magic branch numbers}).  The branch 1.1.1 has a
special meaning.  @xref{Tracking sources}.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Versions revisions releases
@section Versions, revisions and releases
@cindex Revisions, versions and releases
@cindex Versions, revisions and releases
@cindex Releases, revisions and versions

A file can have several versions, as described above.
Likewise, a software product can have several versions.
A software product is often given a version number such
as @samp{4.1.1}.

Versions in the first sense are called @dfn{revisions}
in this document, and versions in the second sense are
called @dfn{releases}.  To avoid confusion, the word
@dfn{version} is almost never used in this document.

@c ---------------------------------------------------------------------
@node A sample session
@chapter A sample session
@cindex A sample session
@cindex Example of a work-session
@cindex Getting started
@cindex Work-session, example of
@cindex tc, Trivial Compiler (example)
@cindex Trivial Compiler (example)

This section describes a typical work-session using
@sc{cvs}.  It assumes that a repository is set up
(@pxref{Repository}).

Suppose you are working on a simple compiler.  The source
consists of a handful of C files and a @file{Makefile}.
The compiler is called @samp{tc} (Trivial Compiler),
and the repository is set up so that there is a module
called @samp{tc}.

@menu
* Getting the source::          Creating a workspace
* Committing your changes::     Making your work available to others
* Cleaning up::                 Cleaning up
* Viewing differences::         Viewing differences
@end menu

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Getting the source
@section Getting the source
@cindex Getting the source
@cindex Checking out source
@cindex Fetching source
@cindex Source, getting from CVS
@cindex Checkout, example

The first thing you must do is to get your own working copy of the
source for @samp{tc}.  For this, you use the @code{checkout} command:

@example
$ cvs checkout tc
@end example

@noindent
This will create a new directory called @file{tc} and populate it with
the source files.

@example
$ cd tc
$ ls tc
CVS         Makefile    backend.c   driver.c    frontend.c  parser.c
@end example

The @file{CVS} directory is used internally by
@sc{cvs}.  Normally, you should not modify or remove
any of the files in it.

You start your favorite editor, hack away at @file{backend.c}, and a couple
of hours later you have added an optimization pass to the compiler.
A note to @sc{rcs} and @sc{sccs} users: There is no need to lock the files that
you want to edit.  @xref{Multiple developers} for an explanation.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Committing your changes
@section Committing your changes
@cindex Committing changes
@cindex Log message entry
@cindex CVSEDITOR, environment variable
@cindex EDITOR, environment variable

When you have checked that the compiler is still compilable you decide
to make a new version of @file{backend.c}.

@example
$ cvs commit backend.c
@end example

@noindent
@sc{cvs} starts an editor, to allow you to enter a log
message.  You type in ``Added an optimization pass.'',
save the temporary file, and exit the editor.

The environment variable @code{$CVSEDITOR} determines
which editor is started.  If @code{$CVSEDITOR} is not
set, then if the environment variable @code{$EDITOR} is
set, it will be used. If both @code{$CVSEDITOR} and
@code{$EDITOR} are not set then the editor defaults to
@code{vi}.  If you want to avoid the overhead of
starting an editor you can specify the log message on
the command line using the @samp{-m} flag instead, like
this:

@example
$ cvs commit -m "Added an optimization pass" backend.c
@end example

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Cleaning up
@section Cleaning up
@cindex Cleaning up
@cindex Working copy, removing
@cindex Removing your working copy
@cindex Releasing your working copy

Before you turn to other tasks you decide to remove your working copy of
tc.  One acceptable way to do that is of course

@example
$ cd ..
$ rm -r tc
@end example

@noindent
but a better way is to use the @code{release} command (@pxref{release}):

@example
$ cd ..
$ cvs release -d tc
M driver.c
? tc
You have [1] altered files in this repository.
Are you sure you want to release (and delete) module `tc': n
** `release' aborted by user choice.
@end example

The @code{release} command checks that all your modifications have been
committed.  If history logging is enabled it also makes a note in the
history file.  @xref{history file}.

When you use the @samp{-d} flag with @code{release}, it
also removes your working copy.

In the example above, the @code{release} command wrote a couple of lines
of output.  @samp{? tc} means that the file @file{tc} is unknown to @sc{cvs}.
That is nothing to worry about: @file{tc} is the executable compiler,
and it should not be stored in the repository.  @xref{cvsignore},
for information about how to make that warning go away.
@xref{release output}, for a complete explanation of
all possible output from @code{release}.

@samp{M driver.c} is more serious.  It means that the
file @file{driver.c} has been modified since it was
checked out.

The @code{release} command always finishes by telling
you how many modified files you have in your working
copy of the sources, and then asks you for confirmation
before deleting any files or making any note in the
history file.

You decide to play it safe and answer @kbd{n @key{RET}}
when @code{release} asks for confirmation.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Viewing differences
@section Viewing differences
@cindex Viewing differences
@cindex Diff

You do not remember modifying @file{driver.c}, so you want to see what
has happened to that file.

@example
$ cd tc
$ cvs diff driver.c
@end example

This command runs @code{diff} to compare the version of @file{driver.c}
that you checked out with your working copy.  When you see the output
you remember that you added a command line option that enabled the
optimization pass.  You check it in, and release the module.

@example
$ cvs commit -m "Added an optimization pass" driver.c
Checking in driver.c;
/usr/local/cvsroot/tc/driver.c,v  <--  driver.c
new revision: 1.2; previous revision: 1.1
done
$ cd ..
$ cvs release -d tc
? tc
You have [0] altered files in this repository.
Are you sure you want to release (and delete) module `tc': y
@end example

@c ---------------------------------------------------------------------
@node Repository
@chapter The Repository
@cindex Repository, example
@cindex Layout of repository
@cindex Typical repository
@cindex CVSROOT, environment variable
@cindex .profile
@cindex .cshrc
@cindex .tcshrc
@cindex .bashrc
@cindex /usr/local/cvsroot
@cindex cvsroot

Figure 3 below shows a typical setup of a repository.
Only directories are shown below.

@example
@t{/usr}
 |
 +--@t{local}
 |   |
 |   +--@t{cvsroot}
 |   |    | 
 |   |    +--@t{CVSROOT}
          |      (administrative files) 
          | 
          +--@t{gnu}
          |   | 
          |   +--@t{diff}
          |   |   (source code to @sc{gnu} diff) 
          |   | 
          |   +--@t{rcs}
          |   |   (source code to @sc{rcs})
          |   | 
          |   +--@t{cvs}
          |       (source code to @sc{cvs}) 
          | 
          +--@t{yoyodyne}
              | 
              +--@t{tc}
              |    |
              |    +--@t{man}
              |    |
              |    +--@t{testing}
              | 
              +--(other Yoyodyne software)
@end example                              


There are a couple of different ways to tell @sc{cvs}
where to find the repository.  You can name the
repository on the command line explicitly, with the
@code{-d} (for "directory") option:

@example
cvs -d /usr/local/cvsroot checkout yoyodyne/tc
@end example

        Or you can set the @code{$CVSROOT} environment
variable to an absolute path to the root of the
repository, @file{/usr/local/cvsroot} in this example.
To set @code{$CVSROOT}, all @code{csh} and @code{tcsh}
users should have this line in their @file{.cshrc} or
@file{.tcshrc} files:

@example
setenv CVSROOT /usr/local/cvsroot
@end example

@noindent
@code{sh} and @code{bash} users should instead have these lines in their
@file{.profile} or @file{.bashrc}:

@example
CVSROOT=/usr/local/cvsroot
export CVSROOT
@end example

        A repository specified with @code{-d} will
override the @code{$CVSROOT} environment variable.
Once you've checked a working copy out from the
repository, it will remember where its repository is
(the information is recorded in the
@file{CVS/Root} file in the working copy).  

The @code{-d} option and the @file{CVS/Root} file
both override the @code{$CVSROOT} environment variable;
however, @sc{CVS} will complain if the @file{-d}
argument and the @file{CVS/Root} file disagree.

There is nothing magical about the name
@file{/usr/local/cvsroot}.  You can choose to place the
repository anywhere you like.  
@xref{Remote repositories} to learn how the repository can be on a
different machine than your working copy of the sources.

The repository is split in two parts.  @file{$CVSROOT/CVSROOT} contains
administrative files for @sc{cvs}.  The other directories contain the actual
user-defined modules.

@menu
* User modules::                The structure of the repository
* Intro administrative files::  Defining modules
* Multiple repositories::       Multiple repositories
* Creating a repository::       Creating a repository
* Remote repositories::         Accessing repositories on remote machines
@end menu

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node User modules
@section User modules
@cindex User modules
@cindex Repository, user parts

@example
  @code{$CVSROOT}
    |
    +--@t{yoyodyne}
    |   |
    |   +--@t{tc}
    |   |   |
            +--@t{Makefile,v}
            +--@t{backend.c,v}
            +--@t{driver.c,v}
            +--@t{frontend.c,v}
            +--@t{parser.c,v}
            +--@t{man}
            |    |
            |    +--@t{tc.1,v}
            |     
            +--@t{testing}
                 |
                 +--@t{testpgm.t,v}
                 +--@t{test2.t,v}
@end example

@cindex History files
@cindex RCS history files
@cindex RCS, CVS uses RCS
The figure above shows the contents of the @samp{tc}
module inside the repository.  As you can see all file
names end in @samp{,v}.  The files are @dfn{history
files}.  They contain, among other things, enough
information to recreate any revision of the file, a log
of all commit messages and the user-name of the person
who committed the revision.  @sc{cvs} uses the
facilities of @sc{rcs}, a simpler version control
system, to maintain these files.  For a full
description of the file format, see the @code{man} page
@cite{rcsfile(5)}.
@c -- Use this format for all references to man pages,
@c -- or use something better!

@menu
* File permissions::            File permissions
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node File permissions
@subsection File permissions
@c -- Move this to @node Setting up
@cindex Security
@cindex File permissions
@cindex Group
All @samp{,v} files are created read-only, and you
should not change the permission of those files.  The
directories inside the repository should be writable by
the persons that have permission to modify the files in
each directory.  This normally means that you must
create a UNIX group (see group(5)) consisting of the
persons that are to edit the files in a project, and
set up the repository so that it is that group that
owns the directory.

This means that you can only control access to files on
a per-directory basis.

@sc{cvs} tries to set up reasonable file permissions
for new directories that are added inside the tree, but
you must fix the permissions manually when a new
directory should have different permissions than its
parent directory.

@cindex setuid
@cindex setgid
Since @sc{cvs} was not written to be run setuid, it is
unsafe to try to run it setuid.  You cannot use the
setuid features of @sc{rcs} together with @sc{cvs}.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Intro administrative files
@section The administrative files
@cindex Administrative files (intro)
@cindex Modules file
@cindex CVSROOT, module name
@cindex Defining modules (intro)

The directory @file{$CVSROOT/CVSROOT} contains some @dfn{administrative
files}.  @xref{Administrative files}, for a complete description.
You can use @sc{cvs} without any of these files, but
some commands work better when at least the
@file{modules} file is properly set up.

The most important of these files is the @file{modules}
file.  It defines all modules in the repository.  This
is a sample @file{modules} file.

@c FIXME: The CVSROOT line is a goofy example now that
@c mkmodules doesn't exist.
@example
CVSROOT         CVSROOT
modules         CVSROOT modules
cvs             gnu/cvs
rcs             gnu/rcs
diff            gnu/diff
tc              yoyodyne/tc
@end example

The @file{modules} file is line oriented.  In its simplest form each
line contains the name of the module, whitespace, and the directory
where the module resides.  The directory is a path relative to
@code{$CVSROOT}.  The last for lines in the example
above are examples of such lines.

@c FIXME: might want to introduce the concept of options in modules file
@c (the old example which was here, -i mkmodules, is obsolete).

The line that defines the module called @samp{modules}
uses features that are not explained here.
@xref{modules}, for a full explanation of all the
available features.

@subsection Editing administrative files
@cindex Editing administrative files
@cindex Administrative files, editing them

You edit the administrative files in the same way that you would edit
any other module.  Use @samp{cvs checkout CVSROOT} to get a working
copy, edit it, and commit your changes in the normal way.

It is possible to commit an erroneous administrative
file.  You can often fix the error and check in a new
revision, but sometimes a particularly bad error in the
administrative file makes it impossible to commit new
revisions.  
@c @xref{Bad administrative files} for a hint
@c about how to solve such situations.
@c -- administrative file checking--

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Multiple repositories
@section Multiple repositories
@cindex Multiple repositories
@cindex Repositories, multiple
@cindex Many repositories
@cindex Parallel repositories
@cindex Disjoint repositories
@cindex CVSROOT, multiple repositories

In some situations it is a good idea to have more than
one repository, for instance if you have two
development groups that work on separate projects
without sharing any code.  All you have to do to have
several repositories is to specify the appropriate
repository, using the @code{CVSROOT} environment
variable, the @samp{-d} option to @sc{cvs}, or (once
you have checked out a working directories) by
simply allowing @sc{cvs} to use the repository that was
used to check out the working directory (@pxref{Repository}).

Notwithstanding, it can be confusing to have two or
more repositories.

None of the examples in this manual show multiple
repositories.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Creating a repository
@section Creating a repository
@c -- Well, how do you do?

See the instructions in the @file{INSTALL} file in the
@sc{cvs} distribution.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Remote repositories
@section Remote repositories
@cindex Repositories, remote
@cindex Remote repositories
@cindex Client/Server Operation

        Your working copy of the sources can be on a
different machine than the repository.  Generally,
using a remote repository is just like using a local
one, except that the format of the repository name is:

@example
        user@@hostname:/path/to/repository
@end example

The details of exactly what needs to be set up depend
on how you are connecting to the server.

@menu
* Connecting via rsh::          Using the @code{rsh} program to connect
* Password authenticated::      Direct connections using passwords
* Kerberos authenticated::      Direct connections with kerberos
@end menu

@node Connecting via rsh
@subsection Connecting with rsh

@cindex rsh
CVS uses the @file{rsh} protocol to perform these
operations, so the remote user host needs to have a
@file{.rhosts} file which grants access to the local
user.

For example, suppose you are the user @file{mozart} on
the local machine @file{anklet.grunge.com}, and the
server machine is @file{chainsaw.brickyard.com}.  On
chainsaw, put the following line into the file
@file{.rhosts} in @file{bach}'s home directory:

@example
anklet.grunge.com  mozart
@end example

Then test that @code{rsh} is working with

@example
rsh -l bach chainsaw.brickyard.com echo $PATH
@end example

@cindex CVS_SERVER
Next you have to make sure that @code{rsh} will be able
to find the server.  Make sure that the path which
@code{rsh} printed in the above example includes the
directory containing a program named @code{cvs} which
is the server.  You need to set the path in
@file{.bashrc}, @file{.cshrc}, etc., not @file{.login}
or @file{.profile}.  Alternately, you can set the
environment variable @code{CVS_SERVER} on the client
machine to the filename of the server you want to use,
for example @file{/usr/local/bin/cvs-1.6}.

There is no need to edit @code{inetd.conf} or start a
@sc{cvs} server daemon.

Continuing our example, supposing you want to access
the module @file{foo} in the repository
@file{/usr/local/cvsroot/}, on machine
@file{chainsaw.brickyard.com}, you are ready to go:

@example
cvs -d bach@@chainsaw.brickyard.com:/user/local/cvsroot checkout foo
@end example

(The @file{bach@@} can be omitted if the username is
the same on both the local and remote hosts.)

@node Password authenticated
@subsection Direct connection with password authentication

The @sc{cvs} client can also connect to the server
using a password protocol.  This is particularly useful
if using @code{rsh} is not feasible (for example,
the server is behind a firewall), and Kerberos also is
not available.

        To use this method, it is necessary to make
some adjustments on both the server and client sides.

@menu
* Password authentication server::     Setting up the server
* Password authentication client::     Using the client
* Password authentication security::   What this method does and does not do
@end menu

@node Password authentication server
@subsubsection Setting up the server for password authentication

@cindex Pserver (subcommand)
@cindex password server, setting up
@cindex authenticating server, setting up
On the server side, the file @file{/etc/inetd.conf}
needs to be edited so @code{inetd} knows to run the
command @code{cvs pserver} when it receives a
connection on the right port.  By default, the port
number is 2401; it would be different if your client
were compiled with @code{CVS_AUTH_PORT} defined to
something else, though.

        If your @code{inetd} allows raw port numbers in
@file{/etc/inetd.conf}, then the following (all on a
single line in @file{inetd.conf}) should be sufficient:

@example
2401  stream  tcp  nowait  root  /usr/local/bin/cvs
cvs -b /usr/local/bin pserver
@end example

The @samp{-b} option specifies the directory which contains
the @sc{rcs} binaries on the server.

        If your @code{inetd} wants a symbolic service
name instead of a raw port number, then put this in
@file{/etc/services}:

@example
cvspserver      2401/tcp
@end example

        and put @code{cvspserver} instead of
@code{2401} in @file{inetd.conf}.

        Once the above is taken care of, restart your
@code{inetd}, or do whatever is necessary to force it
to reread its initialization files.

@cindex CVS passwd file
@cindex passwd file
Because the client stores and transmits passwords in
cleartext (almost---see @ref{Password authentication
security} for details), a separate @sc{cvs} password
file may be used, so people don't compromise their
regular passwords when they access the repository.
This file is @file{$CVSROOT/CVSROOT/passwd}
(@pxref{Intro administrative files}).  Its format is
similar to @file{/etc/passwd}, except that it only has
two fields, username and password.  For example:

@example
bach:ULtgRLXo7NRxs
cwang:1sOp854gDF3DY
@end example

The password is encrypted according to the standard
Unix @code{crypt()} function, so it is possible to
paste in passwords directly from regular Unix
@file{passwd} files.

When authenticating a password, the server first checks
for the user in the @sc{cvs} @file{passwd} file.  If it
finds the user, it compares against that password.  If
it does not find the user, or if the @sc{cvs}
@file{passwd} file does not exist, then the server
tries to match the password using the system's
user-lookup routine.  When using the @sc{cvs}
@file{passwd} file, the server runs under as the
username specified in the the third argument in the
entry, or as the first argument if there is no third
argument (in this way @sc{cvs} allows imaginary
usernames provided the @sc{cvs} @file{passwd} file
indicates corresponding valid system usernames).  In
any case, @sc{cvs} will have no privileges which the
(valid) user would not have.

Right now, the only way to put a password in the
@sc{cvs} @file{passwd} file is to paste it there from
somewhere else.  Someday, there may be a @code{cvs
passwd} command.

@node Password authentication client
@subsubsection Using the client with password authentication
@cindex Login (subcommand)
@cindex password client, using
@cindex authenticated client, using
Before connecting to the server, the client must @dfn{log
in} with the command @code{cvs login}.  Logging in
verifies a password with the server, and also records
the password for later transactions with the server.
The @code{cvs login} command needs to know the
username, server hostname, and full repository path,
and it gets this information from the repository
argument or the @code{CVSROOT} environment variable.

@code{cvs login} is interactive --- it prompts for a
password:

@example
cvs -d bach@@chainsaw.brickyard.com:/usr/local/cvsroot login 
CVS password: 
@end example

The password is checked with the server; if it is
correct, the @code{login} succeeds, else it fails,
complaining that the password was incorrect.

Once you have logged in, you can force @sc{cvs} to
connect directly to the server and authenticate with
the stored password by prefixing the repository with
@samp{:pserver:}:

@example
cvs -d :pserver:bach@@chainsaw.brickyard.com:/usr/local/cvsroot checkout foo
@end example

The @samp{:pserver:} is necessary because without it,
@sc{cvs} will assume it should use @code{rsh} to
connect with the server (@pxref{Connecting via rsh}).
(Once you have a working copy checked out and are
running @sc{cvs} commands from within it, there is no
longer any need to specify the repository explicitly,
because @sc{cvs} records it in the working copy's
@file{CVS} subdirectory.)

@cindex CVS_PASSFILE, environment variable
Passwords are stored by default in the file
@file{$HOME/.cvspass}.  Its format is human-readable,
but don't edit it unless you know what you are doing.
The passwords are not stored in cleartext, but are
trivially encoded to protect them from "innocent"
compromise (i.e., inadvertently being seen by a system
administrator who happens to look at that file).

The @code{CVS_PASSFILE} environment variable overrides
this default.  If you use this variable, make sure you
set it @emph{before} @code{cvs login} is run.  If you
were to set it after running @code{cvs login}, then
later @sc{cvs} commands would be unable to look up the
password for transmission to the server.

@cindex CVS_PASSWORD, environment variable
The @code{CVS_PASSWORD} environment variable overrides
@emph{all} stored passwords.  If it is set, @sc{cvs}
will use it for all password-authenticated
connections.

@node Password authentication security
@subsubsection Security considerations with password authentication

The passwords are stored on the client side in a
trivial encoding of the cleartext, and transmitted in
the same encoding.  The encoding is done only to
prevent inadvertent password compromises (i.e., a
system administrator accidentally looking at the file),
and will not prevent even a naive attacker from gaining
the password.

The separate @sc{cvs} password file (@pxref{Password
authentication server}) allows people
to use a different password for repository access than
for login access.  On the other hand, once a user has
access to the repository, she can execute programs on
the server system through a variety of means.  Thus, repository
access implies fairly broad system access as well.  It
might be possible to modify @sc{cvs} to prevent that,
but no one has done so as of this writing.
Furthermore, there may be other ways in which having
access to @sc{cvs} allows people to gain more general
access to the system; noone has done a careful audit.

In summary, anyone who gets the password gets
repository access, and some measure of general system
access as well.  The password is available to anyone
who can sniff network packets or read a protected
(i.e., user read-only) file.  If you want real
security, get Kerberos.

@node Kerberos authenticated
@subsection Direct connection with kerberos

@cindex kerberos
The main disadvantage of using rsh is that all the data
needs to pass through additional programs, so it may be
slower.  So if you have kerberos installed you can
connect via a direct @sc{tcp} connection,
authenticating with kerberos (note that the data
transmitted is @emph{not} encrypted).

To do this, @sc{cvs} needs to be compiled with kerberos
support; when configuring @sc{cvs} it tries to detect
whether kerberos is present or you can use the
@file{--with-krb4} flag to configure.

@cindex CVS_CLIENT_PORT
You need to edit @code{inetd.conf} on the server
machine to run @code{cvs kserver}.  The client uses
port 1999 by default; if you want to use another port
specify it in the @code{CVS_CLIENT_PORT} environment
variable on the client.  Set @code{CVS_CLIENT_PORT} to
@samp{-1} to force an rsh connection.

@cindex kinit
When you want to use @sc{cvs}, get a ticket in the
usual way (generally @code{kinit}); it must be a ticket
which allows you to log into the server machine.  Then
you are ready to go:

@example
cvs -d chainsaw.brickyard.com:/user/local/cvsroot checkout foo
@end example

If @sc{cvs} fails to connect, it will fall back to
trying rsh.

@c ---------------------------------------------------------------------
@node Starting a new project
@chapter Starting a project with CVS
@cindex Starting a project with CVS
@cindex Creating a project

@comment --moduledb--
Since @sc{cvs} 1.x is bad at renaming files and moving
them between directories, the first thing you do when
you start a new project should be to think through your
file organization.  It is not impossible---just
awkward---to rename or move files.
@xref{Moving files}.

What to do next depends on the situation at hand.

@menu
* Setting up the files::        Getting the files into the repository
* Defining the module::         How to make a module of the files
@end menu
@c -- File permissions!

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Setting up the files
@section Setting up the files

The first step is to create the files inside the repository.  This can
be done in a couple of different ways.

@c -- The contributed scripts
@menu
* From files::                  This method is useful with old projects
                                where files already exists.
* From other version control systems::  Old projects where you want to
                                        preserve history from another system.
* From scratch::                Creating a module from scratch.
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node From files
@subsection Creating a module from a number of files
@cindex Importing files

When you begin using @sc{cvs}, you will probably already have several
projects that can be
put under @sc{cvs} control.  In these cases the easiest way is to use the
@code{import} command.  An example is probably the easiest way to
explain how to use it.  If the files you want to install in
@sc{cvs} reside in @file{@var{dir}}, and you want them to appear in the
repository as @file{$CVSROOT/yoyodyne/@var{dir}}, you can do this:

@example
$ cd @var{dir}
$ cvs import -m "Imported sources" yoyodyne/@var{dir} yoyo start
@end example

Unless you supply a log message with the @samp{-m}
flag, @sc{cvs} starts an editor and prompts for a
message.  The string @samp{yoyo} is a @dfn{vendor tag},
and @samp{start} is a @dfn{release tag}.  They may fill
no purpose in this context, but since @sc{cvs} requires
them they must be present.  @xref{Tracking sources}, for
more information about them.

You can now verify that it worked, and remove your
original source directory.

@example
$ cd ..
$ mv @var{dir} @var{dir}.orig
$ cvs checkout yoyodyne/@var{dir}       # @r{Explanation below}
$ ls -R yoyodyne
$ rm -r @var{dir}.orig
@end example

@noindent
Erasing the original sources is a good idea, to make sure that you do
not accidentally edit them in @var{dir}, bypassing @sc{cvs}.
Of course, it would be wise to make sure that you have
a backup of the sources before you remove them.

The @code{checkout} command can either take a module
name as argument (as it has done in all previous
examples) or a path name relative to @code{$CVSROOT},
as it did in the example above.

It is a good idea to check that the permissions
@sc{cvs} sets on the directories inside @samp{$CVSROOT}
are reasonable, and that they belong to the proper
groups.  @xref{File permissions}.

@c The node name is too long, but I am having trouble
@c thinking of something more concise.
@node From other version control systems
@subsection Creating Files From Other Version Control Systems
@cindex Importing files, from other version control systesm

If you have a project which you are maintaining with
another version control system, such as @sc{rcs}, you
may wish to put the files from that project into
@sc{cvs}, and preserve the revision history of the
files.

@table @asis
@cindex RCS, importing files from
@item From RCS
If you have been using @sc{rcs}, find the @sc{rcs}
files---usually a file named @file{foo.c} will have its
@sc{rcs} file in @file{RCS/foo.c,v} (but it could be
other places; consult the @sc{rcs} documentation for
details).  Then create the appropriate directories in
@sc{cvs} if they do not already exist.  Then copy the
files into the appropriate directories in the @sc{cvs}
repository (the name in the repository must be the name
of the source file with @samp{,v} added; the files go
directly in the appopriate directory of the repository,
not in an @file{RCS} subdirectory).  This is one of the
few times when it is a good idea to access the @sc{cvs}
repository directly, rather than using @sc{cvs}
commands.  Then you are ready to check out a new
working directory.
@c Someday there probably should be a "cvs import -t
@c rcs" or some such.  It could even create magic
@c branches.  It could also do something about the case
@c where the RCS file had a (non-magic) "0" branch.

@c How many is "many"? Or do they just import RCS files?
@item From another version control system
Many version control systems have the ability to export
@sc{rcs} files in the standard format.  If yours does,
export the @sc{rcs} files and then follow the above
instructions.

@cindex SCCS, importing files from
@item From SCCS
There is a script in the @file{contrib} directory of
the @sc{cvs} source distribution called @file{sccs2rcs}
which converts @sc{sccs} files to @sc{rcs} files.
Note: you must run it on a machine which has both
@sc{sccs} and @sc{rcs} installed, and like everything
else in contrib it is unsupported (your mileage may
vary).
@end table

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node From scratch
@subsection Creating a module from scratch

For a new project, the easiest thing to do is probably
to create an empty directory structure, like this:

@example
$ mkdir tc
$ mkdir tc/man
$ mkdir tc/testing
@end example

After that, you use the @code{import} command to create
the corresponding (empty) directory structure inside
the repository:

@example
$ cd tc
$ cvs import -m "Created directory structure" yoyodyne/@var{dir} yoyo start
@end example

Then, use @code{add} to add files (and new directories)
as they appear.

Check that the permissions @sc{cvs} sets on the
directories inside @samp{$CVSROOT} are reasonable.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Defining the module
@section Defining the module
@cindex Defining a module
@cindex Editing the modules file
@cindex Module, defining
@cindex Modules file, changing

The next step is to define the module in the
@file{modules} file.  This is not strictly necessary,
but modules can be convenient in grouping together
related files and directories.

In simple cases these steps are sufficient to define a module.

@enumerate
@item
Get a working copy of the modules file.

@example
$ cvs checkout modules
$ cd modules
@end example

@item
Edit the file and insert a line that defines the module.  @xref{Intro
administrative files}, for an introduction.  @xref{modules}, for a full
description of the modules file.  You can use the
following line to define the module @samp{tc}:

@example
tc   yoyodyne/tc
@end example

@item
Commit your changes to the modules file.

@example
$ cvs commit -m "Added the tc module." modules
@end example

@item
Release the modules module.

@example
$ cd ..
$ cvs release -d modules
@end example
@end enumerate

@c ---------------------------------------------------------------------
@node Multiple developers
@chapter Multiple developers
@cindex Multiple developers
@cindex Team of developers
@cindex File locking
@cindex Locking files
@cindex Working copy

When more than one person works on a software project
things often get complicated.  Often, two people try to
edit the same file simultaneously.  Some other version
control systems (including @sc{rcs} and @sc{sccs})
try to solve that particular problem by introducing
@dfn{file locking}, so that only one person can edit
each file at a time.  Unfortunately, file locking can
be very counter-productive.  If two persons want
to edit different parts of a file, there may be no
reason to prevent either of them from doing so.

@sc{cvs} does not use file locking.  Instead, it allows many
people to edit their own @dfn{working copy} of a file
simultaneously.  The first person that commits his
changes has no automatic way of knowing that another has started to
edit it.  Others will get an error message when they
try to commit the file.  They must then use @sc{cvs}
commands to bring their working copy up to date with
the repository revision.  This process is almost
automatic, and explained in this chapter.

There are many ways to organize a team of developers.
@sc{cvs} does not try to enforce a certain
organization.  It is a tool that can be used in several
ways.  It is often useful to inform the group of
commits you have done.  @sc{cvs} has several ways of
automating that process.  @xref{Informing others}.
@xref{Revision management}, for more tips on how to use
@sc{cvs}.

@menu
* File status::                 A file can be in several states
* Updating a file::             Bringing a file up-to-date
* Conflicts example::           An informative example
* Informing others::            To cooperate you must inform
* Concurrency::                 Simultaneous repository access
* Watches::                     Mechanisms to track who is editing files
@end menu

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node File status
@section File status
@cindex File status
@cindex Status of a file
@cindex Four states of a file

After you have checked out a file out from @sc{cvs}, it is in
one of these four states:

@table @asis
@cindex Up-to-date
@item Up-to-date
The file is identical with the latest revision in the
repository.
@c -- The above is not always true if branching is used.

@item Locally modified
@cindex Locally modified
You have edited the file, and not yet committed your changes.

@item Needing update
@cindex Needing update
Someone else has committed a newer revision to the repository.

@item Needing merge
@cindex Needing merge
Someone else have committed a newer revision to the repository, and you
have also made modifications to the file.
@c -- What about "added" "removed" and so on?
@end table

You can use the @code{status} command to find out the status of a given
file.  @xref{status}.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Updating a file
@section Bringing a file up to date
@cindex Bringing a file up to date
@cindex Updating a file
@cindex Merging a file
@cindex update, introduction

When you want to update or merge a file, use the @code{update}
command.  For files that are not up to date this is roughly equivalent
to a @code{checkout} command: the newest revision of the file is
extracted from the repository and put in your working copy of the
module.

Your modifications to a file are never lost when you
use @code{update}.  If no newer revision exists,
running @code{update} has no effect.  If you have
edited the file, and a newer revision is available,
@sc{cvs} will merge all changes into your working copy.

For instance, imagine that you checked out revision 1.4 and started
editing it.  In the meantime someone else committed revision 1.5, and
shortly after that revision 1.6.  If you run @code{update} on the file
now, @sc{cvs} will incorporate all changes between revision 1.4 and 1.6 into
your file.

@cindex Overlap
If any of the changes between 1.4 and 1.6 were made too
close to any of the changes you have made, an
@dfn{overlap} occurs.  In such cases a warning is
printed, and the resulting file includes both
versions of the lines that overlap, delimited by
special markers.
@xref{update}, for a complete description of the
@code{update} command.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Conflicts example
@section Conflicts example
@cindex Merge, an example
@cindex Example of merge
@cindex driver.c (merge example)

Suppose revision 1.4 of @file{driver.c} contains this:

@example
#include <stdio.h>

void main()
@{
    parse();
    if (nerr == 0)
        gencode();
    else
        fprintf(stderr, "No code generated.\n");
    exit(nerr == 0 ? 0 : 1);
@}
@end example

@noindent
Revision 1.6 of @file{driver.c} contains this:

@example
#include <stdio.h>

int main(int argc,
         char **argv)
@{
    parse();
    if (argc != 1)
    @{
        fprintf(stderr, "tc: No args expected.\n");
        exit(1);
    @}
    if (nerr == 0)
        gencode();
    else
        fprintf(stderr, "No code generated.\n");
    exit(!!nerr);
@}
@end example

@noindent
Your working copy of @file{driver.c}, based on revision
1.4, contains this before you run @samp{cvs update}:
@c -- Really include "cvs"?

@example
#include <stdlib.h>
#include <stdio.h>

void main()
@{
    init_scanner();
    parse();
    if (nerr == 0)
        gencode();
    else
        fprintf(stderr, "No code generated.\n");
    exit(nerr == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
@}
@end example

@noindent
You run @samp{cvs update}:
@c -- Really include "cvs"?

@example
$ cvs update driver.c
RCS file: /usr/local/cvsroot/yoyodyne/tc/driver.c,v
retrieving revision 1.4
retrieving revision 1.6
Merging differences between 1.4 and 1.6 into driver.c
rcsmerge warning: overlaps during merge
cvs update: conflicts found in driver.c
C driver.c
@end example

@noindent
@cindex Conflicts (merge example)
@sc{cvs} tells you that there were some conflicts.
Your original working file is saved unmodified in
@file{.#driver.c.1.4}.  The new version of
@file{driver.c} contains this:

@example
#include <stdlib.h>
#include <stdio.h>

int main(int argc,
         char **argv)
@{
    init_scanner();
    parse();
    if (argc != 1)
    @{
        fprintf(stderr, "tc: No args expected.\n");
        exit(1);
    @}
    if (nerr == 0)
        gencode();
    else
        fprintf(stderr, "No code generated.\n");
<<<<<<< driver.c
    exit(nerr == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
=======
    exit(!!nerr);
>>>>>>> 1.6
@}
@end example

@noindent
@cindex Markers, conflict
@cindex Conflict markers
@cindex <<<<<<<
@cindex >>>>>>>
@cindex =======

Note how all non-overlapping modifications are incorporated in your working
copy, and that the overlapping section is clearly marked with
@samp{<<<<<<<}, @samp{=======} and @samp{>>>>>>>}.

@cindex Resolving a conflict
@cindex Conflict resolution
You resolve the conflict by editing the file, removing the markers and
the erroneous line.  Suppose you end up with this file:
@c -- Add xref to the pcl-cvs manual when it talks
@c -- about this.
@example
#include <stdlib.h>
#include <stdio.h>

int main(int argc,
         char **argv)
@{
    init_scanner();
    parse();
    if (argc != 1)
    @{
        fprintf(stderr, "tc: No args expected.\n");
        exit(1);
    @}
    if (nerr == 0)
        gencode();
    else
        fprintf(stderr, "No code generated.\n");
    exit(nerr == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
@}
@end example

@noindent
You can now go ahead and commit this as revision 1.7.

@example
$ cvs commit -m "Initialize scanner. Use symbolic exit values." driver.c
Checking in driver.c;
/usr/local/cvsroot/yoyodyne/tc/driver.c,v  <--  driver.c
new revision: 1.7; previous revision: 1.6
done
@end example

@cindex emerge
If you use release 1.04 or later of pcl-cvs (a @sc{gnu}
Emacs front-end for @sc{cvs}) you can use an Emacs
package called emerge to help you resolve conflicts.
See the documentation for pcl-cvs.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Informing others
@section Informing others about commits
@cindex Informing others
@cindex Spreading information
@cindex Mail, automatic mail on commit

It is often useful to inform others when you commit a
new revision of a file.  The @samp{-i} option of the
@file{modules} file, or the @file{loginfo} file, can be
used to automate this process.  @xref{modules}.
@xref{loginfo}.  You can use these features of @sc{cvs}
to, for instance, instruct @sc{cvs} to mail a
message to all developers, or post a message to a local
newsgroup.
@c -- More text would be nice here.

@node Concurrency
@section Several developers simultaneously attempting to run CVS

@cindex locks, cvs
If several developers try to run @sc{cvs} at the same
time, one may get the following message:

@example
[11:43:23] waiting for bach's lock in /usr/local/cvsroot/foo
@end example

@sc{cvs} will try again every 30 seconds, and either
continue with the operation or print the message again,
if it still needs to wait.  If a lock seems to stick
around for an undue amount of time, find the person
holding the lock and ask them about the cvs command
they are running.  If they aren't running a cvs
command, look for and remove files starting with
@file{#cvs.tfl}, @file{#cvs.rfl}, or @file{#cvs.wfl}
from the repository.

Note that these locks are to protect @sc{cvs}'s
internal data structures and have no relationship to
the word @dfn{lock} in the sense used by @sc{rcs}--a
way to prevent other developers from working on a
particular file.

Any number of people can be reading from a given
repository at a time; only when someone is writing do
the locks prevent other people from reading or writing.

@cindex Atomic transactions, lack of
@cindex Transactions, atomic, lack of
One might hope for the following property

@example
If someone commits some changes in one cvs command,
then an update by someone else will either get all the
changes, or none of them.
@end example

but @sc{cvs} does @emph{not} have this property.  For
example, given the files

@example
a/one.c
a/two.c
b/three.c
b/four.c
@end example

if someone runs

@example
cvs ci a/two.c b/three.c
@end example

and someone else runs @code{cvs update} at the same
time, the person running @code{update} might get only
the change to @file{b/three.c} and not the change to
@file{a/two.c}.

@node Watches
@section Mechanisms to track who is editing files
@cindex Watches

For many groups, use of @sc{cvs} in its default mode is
perfectly satisfactory.  Users may sometimes go to
check in a modification only to find that another
modification has intervened, but they deal with it and
proceed with their check in.  Other groups prefer to be
able to know who is editing what files, so that if two
people try to edit the same file they can choose to
talk about who is doing what when rather than be
surprised at check in time.  The features in this
section allow such coordination, while retaining the
ability of two developers to edit the same file at the
same time.

For maximum benefit developers should use @code{cvs
edit} (not @code{chmod}) to make files read-write to
edit them, and @code{cvs release} (not @code{rm}) to
discard a working directory which is no longer in use,
but @sc{cvs} is not able to enforce this behavior.

@c I'm a little dissatisfied with this presentation,
@c because "watch on"/"edit"/"editors" are one set of
@c functionality, and "watch add"/"watchers" is another
@c which is somewhat orthogonal even though they interact in
@c various ways.  But I think it might be
@c confusing to describe them separately (e.g. "watch
@c add" with loginfo).  I don't know.

@menu
* Setting a watch::             Telling CVS to watch certain files
* Getting Notified::            Telling CVS to notify you
* Editing files::               How to edit a file which is being watched
* Watch information::           Information about who is watching and editing
* Watches Compatibility::       Watches interact poorly with CVS 1.6 or earlier
@end menu

@node Setting a watch
@subsection Telling CVS to watch certain files

To enable the watch features, you first specify that
certain files are to be watched.

@cindex watch on (subcommand)
@deffn Command {cvs watch on} [@code{-l}] files @dots{}

Specify that developers should run @code{cvs edit}
before editing @var{files}.  CVS will create working
copies of @var{files} read-only, to remind developers
to run the @code{cvs edit} command before working on
them.

If @var{files} includes the name of a directory, CVS
arranges to watch all files added to the corresponding
repository directory, and sets a default for files
added in the future; this allows the user to set
notification policies on a per-directory basis.  The
contents of the directory are processed recursively,
unless the @code{-l} option is given.

If @var{files} is omitted, it defaults to the current directory.

@cindex watch off (subcommand)
@end deffn

@deffn Command {cvs watch off} [@code{-l}] files @dots{}

Do not provide notification about work on @var{files}.  CVS will create
working copies of @var{files} read-write.

The @var{files} and @code{-l} arguments are processed as for @code{cvs
watch on}.

@end deffn

@node Getting Notified
@subsection Telling CVS to notify you

You can tell @sc{cvs} that you want to receive
notifications about various actions taken on a file.
You can do this without using @code{cvs watch on} for
the file, but generally you will want to use @code{cvs
watch on}, so that developers use the @code{cvs edit}
command.

@cindex watch add (subcommand)
@deffn Command {cvs watch add} [@code{-a} action] [@code{-l}] files @dots{}

Add the current user to the list of people to receive notification of
work done on @var{files}.

The @code{-a} option specifies what kinds of events CVS should notify
the user about.  @var{action} is one of the following:

@table @code

@item edit
Another user has applied the @code{cvs edit} command (described
below) to a file.

@item unedit
Another user has applied the @code{cvs unedit} command (described
below) or the @code{cvs release} command to a file, or has deleted
the file and allowed @code{cvs update} to recreate it.

@item commit
Another user has committed changes to a file.

@item all
All of the above.

@item none
None of the above.  (This is useful with @code{cvs edit},
described below.)

@end table

The @code{-a} option may appear more than once, or not at all.  If
omitted, the action defaults to @code{all}.

The @var{files} and @code{-l} option are processed as for the
@code{cvs watch} commands.

@end deffn


@cindex watch remove (subcommand)
@deffn Command {cvs watch remove} [@code{-a} action] [@code{-l}] files @dots{}

Remove a notification request established using @code{cvs watch add};
the arguments are the same.  If the @code{-a} option is present, only
watches for the specified actions are removed.

@end deffn

When the conditions exist for notification, @sc{cvs}
calls the @file{notify} administrative file, passing it
the user to receive the notification and the user who
is taking the action which results in notification.
Normally @file{notify} will just send an email message.

@cindex users (admin file)
Note that if you set this up in the straightforward
way, users receive notifications on the server machine.
One could of course write a @file{notify} script which
directed notifications elsewhere, but to make this
easy, @sc{cvs} allows you to associate a notification
address for each user.  To do so create a file
@file{users} in @file{CVSROOT} with a line for each
user in the format @var{user}:@var{value}.  Then
instead of passing the name of the user to be notified
to @file{notify}, @sc{cvs} will pass the @var{value}
(normally an email address on some other machine).

@node Editing files
@subsection How to edit a file which is being watched

Since a file which is being watched is checked out
read-only, you cannot simply edit it.  To make it
read-write, and inform others that you are planning
to edit it, use the @code{cvs edit} command.

@cindex edit (subcommand)
@deffn Command {cvs edit} [options] files @dots{}

Prepare to edit the working files @var{files}.  CVS makes the
@var{files} read-write, and notifies users who have requested
@code{edit} notification for any of @var{files}.

The @code{cvs edit} command accepts the same @var{options} as the
@code{cvs watch add} command, and establishes a temporary watch for the
user on @var{files}; CVS will remove the watch when @var{files} are
@code{unedit}ed or @code{commit}ted.  If the user does not wish to
receive notifications, she should specify @code{-a none}.

The @var{files} and @code{-l} option are processed as for the @code{cvs
watch} commands.

@end deffn

Normally when you are done with a set of changes, you
use the @code{cvs commit} command, which checks in your
changes and returns the watched files to their usual
read-only state.  But if you instead decide to abandon
your changes, or not to make any changes, you can use
the @code{cvs unedit} command.

@cindex unedit (subcommand)
@deffn Command {cvs unedit} [@code{-l}] files @dots{}

Abandon work on the working files @var{files}, and revert them to the
repository versions on which they are based.  CVS makes those
@var{files} read-only for which users have requested notification using
@code{cvs watch on}.  CVS notifies users who have requested @code{unedit}
notification for any of @var{files}.

The @var{files} and @code{-l} option are processed as for the
@code{cvs watch} commands.

@end deffn

When using client/server @sc{cvs}, you can use the
@code{cvs edit} and @code{cvs unedit} commands even if
@sc{cvs} is unable to succesfully communicate with the
server; the notifications will be sent upon the next
successful @sc{cvs} command.

@node Watch information
@subsection Information about who is watching and editing

@cindex watchers (subcommand)
@deffn Command {cvs watchers} [@code{-l}] files @dots{}

List the users currently watching changes to @var{files}.  The report
includes the files being watched, and the mail address of each watcher.

The @var{files} and @code{-l} arguments are processed as for the
@code{cvs watch} commands.

@end deffn


@cindex editors (subcommand)
@deffn Command {cvs editors} [@code{-l}] files @dots{}

List the users currently working on @var{files}.  The report
includes the mail address of each user, the time when the user began
working with the file, and the host and path of the working directory
containing the file.

The @var{files} and @code{-l} arguments are processed as for the
@code{cvs watch} commands.

@end deffn

@node Watches Compatibility
@subsection Using watches with old versions of CVS

@cindex CVS 1.6, and watches
If you use the watch features on a repository, it
creates @file{CVS} directories in the repository and
stores the information about watches in that directory.
If you attempt to use @sc{cvs} 1.6 or earlier with the
repository, you get an error message such as

@example
cvs update: cannot open CVS/Entries for reading: No such file or directory
@end example

and your operation will likely be aborted.  To use the
watch features, you must upgrade all copies of @sc{cvs}
which use that repository in local or server mode.  If
you cannot upgrade, use the @code{watch off} and
@code{watch remove} commands to remove all watches, and
that will restore the repository to a state which
@sc{cvs} 1.6 can cope with.

@c ---------------------------------------------------------------------
@node Branches
@chapter Branches
@cindex Branches
@cindex Main trunk and branches
@cindex Revision tree, making branches

So far, all revisions shown in this manual have been on
the @dfn{main trunk}
of the revision tree, i.e., all revision numbers
have been of the form @var{x}.@var{y}.  One useful
feature, especially when maintaining several releases
of a software product at once, is the ability to make
branches on the revision tree.  @dfn{Tags}, symbolic
names for revisions, will also be
introduced in this chapter.

@menu
* Tags::                        Tags--Symbolic revisions
* Branches motivation::         What branches are good for
* Creating a branch::           Creating a branch
* Sticky tags::                 Sticky tags
@end menu

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Tags
@section Tags--Symbolic revisions
@cindex Tags

The revision numbers live a life of their own.  They
need not have anything at all to do with the release
numbers of your software product.  Depending
on how you use @sc{cvs} the revision numbers might change several times
between two releases.  As an example, some of the
source files that make up @sc{rcs} 5.6 have the following
revision numbers:
@cindex RCS revision numbers

@example
ci.c            5.21
co.c            5.9
ident.c         5.3
rcs.c           5.12
rcsbase.h       5.11
rcsdiff.c       5.10
rcsedit.c       5.11
rcsfcmp.c       5.9
rcsgen.c        5.10
rcslex.c        5.11
rcsmap.c        5.2
rcsutil.c       5.10
@end example

@cindex tag, command, introduction
@cindex Tag, symbolic name
@cindex Symbolic name (tag)
@cindex Name, symbolic (tag)
You can use the @code{tag} command to give a symbolic name to a
certain revision of a file.  You can use the @samp{-v} flag to the
@code{status} command to see all tags that a file has, and
which revision numbers they represent.  Tag names can
contain uppercase and lowercase letters, digits,
@samp{-}, and @samp{_}.  The two tag names @code{BASE}
and @code{HEAD} are reserved for use by @sc{cvs}.  It
is expected that future names which are special to
@sc{cvs} will contain characters such as @samp{%} or
@samp{=}, rather than being named analogously to
@code{BASE} and @code{HEAD}, to avoid conflicts with
actual tag names.
@c FIXME: is the above list of valid characters in tag
@c names complete?

@cindex Adding a tag
@cindex tag, example
The following example shows how you can add a tag to a
file.  The commands must be issued inside your working
copy of the module.  That is, you should issue the
command in the directory where @file{backend.c}
resides.

@example
$ cvs tag release-0-4 backend.c
T backend.c
$ cvs status -v backend.c
===================================================================
File: backend.c         Status: Up-to-date

    Version:            1.4     Tue Dec  1 14:39:01 1992
    RCS Version:        1.4     /usr/local/cvsroot/yoyodyne/tc/backend.c,v
    Sticky Tag:         (none)
    Sticky Date:        (none)
    Sticky Options:     (none)

    Existing Tags:
        release-0-4                     (revision: 1.4)

@end example

There is seldom reason to tag a file in isolation.  A more common use is
to tag all the files that constitute a module with the same tag at
strategic points in the development life-cycle, such as when a release
is made.

@example
$ cvs tag release-1-0 .
cvs tag: Tagging .
T Makefile
T backend.c
T driver.c
T frontend.c
T parser.c
@end example

(When you give @sc{cvs} a directory as argument, it generally applies the
operation to all the files in that directory, and (recursively), to any
subdirectories that it may contain.  @xref{Recursive behavior}.)

@cindex Retrieving an old revision using tags
@cindex Tag, retrieving old revisions
The @code{checkout} command has a flag, @samp{-r}, that lets you check out
a certain revision of a module.  This flag makes it easy to
retrieve the sources that make up release 1.0 of the module @samp{tc} at
any time in the future:

@example
$ cvs checkout -r release-1-0 tc
@end example

@noindent
This is useful, for instance, if someone claims that there is a bug in
that release, but you cannot find the bug in the current working copy.

You can also check out a module as it was at any given date.
@xref{checkout options}.

When you tag more than one file with the same tag you
can think about the tag as "a curve drawn through a
matrix of filename vs. revision number."  Say we have 5
files with the following revisions:

@example
@group
        file1   file2   file3   file4   file5

        1.1     1.1     1.1     1.1  /--1.1*      <-*-  TAG
        1.2*-   1.2     1.2    -1.2*-
        1.3  \- 1.3*-   1.3   / 1.3
        1.4          \  1.4  /  1.4
                      \-1.5*-   1.5
                        1.6
@end group
@end example

At some time in the past, the @code{*} versions were tagged.
You can think of the tag as a handle attached to the curve
drawn through the tagged revisions.  When you pull on
the handle, you get all the tagged revisions.  Another
way to look at it is that you "sight" through a set of
revisions that is "flat" along the tagged revisions,
like this:

@example
@group
        file1   file2   file3   file4   file5

                        1.1
                        1.2
                1.1     1.3                       _
        1.1     1.2     1.4     1.1              /
        1.2*----1.3*----1.5*----1.2*----1.1     (--- <--- Look here
        1.3             1.6     1.3              \_
        1.4                     1.4
                                1.5
@end group
@end example

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Branches motivation
@section What branches are good for
@cindex Branches motivation
@cindex What branches are good for
@cindex Motivation for branches

Suppose that release 1.0 of tc has been made.  You are continuing to
develop tc, planning to create release 1.1 in a couple of months.  After a
while your customers start to complain about a fatal bug.  You check
out release 1.0 (@pxref{Tags}) and find the bug
(which turns out to have a trivial fix).  However, the current revision
of the sources are in a state of flux and are not expected to be stable
for at least another month.  There is no way to make a
bugfix release based on the newest sources.

The thing to do in a situation like this is to create a @dfn{branch} on
the revision trees for all the files that make up
release 1.0 of tc.  You can then make
modifications to the branch without disturbing the main trunk.  When the
modifications are finished you can select to either incorporate them on
the main trunk, or leave them on the branch.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Creating a branch
@section Creating a branch
@cindex Creating a branch
@cindex Branch, creating a
@cindex rtag, creating a branch using

@c FIXME: should be more explicit about the value of
@c having a tag on the branchpoint.  Also should talk
@c about creating a branch with tag not rtag.
The @code{rtag} command can be used to create a branch.
The @code{rtag} command is much like @code{tag}, but it
does not require that you have a working copy of the
module.  @xref{rtag}.  (You can also use the @code{tag}
command; @pxref{tag}).

@example
$ cvs rtag -b -r release-1-0 release-1-0-patches tc
@end example

The @samp{-b} flag makes @code{rtag} create a branch
(rather than just a symbolic revision name).  @samp{-r
release-1-0} says that this branch should be rooted at the node (in
the revision tree) that corresponds to the tag
@samp{release-1-0}.  Note that the numeric revision number that matches
@samp{release-1-0} will probably be different from file to file.  The
name of the new branch is @samp{release-1-0-patches}, and the
module affected is @samp{tc}.

To fix the problem in release 1.0, you need a working
copy of the branch you just created.

@example
$ cvs checkout -r release-1-0-patches tc
$ cvs status -v driver.c backend.c
===================================================================
File: driver.c          Status: Up-to-date

    Version:            1.7     Sat Dec  5 18:25:54 1992
    RCS Version:        1.7     /usr/local/cvsroot/yoyodyne/tc/driver.c,v
    Sticky Tag:         release-1-0-patches (branch: 1.7.2)
    Sticky Date:        (none)
    Sticky Options:     (none)

    Existing Tags:
        release-1-0-patches             (branch: 1.7.2)
        release-1-0                     (revision: 1.7)

===================================================================
File: backend.c         Status: Up-to-date

    Version:            1.4     Tue Dec  1 14:39:01 1992
    RCS Version:        1.4     /usr/local/cvsroot/yoyodyne/tc/backend.c,v
    Sticky Tag:         release-1-0-patches (branch: 1.4.2)
    Sticky Date:        (none)
    Sticky Options:     (none)

    Existing Tags:
        release-1-0-patches             (branch: 1.4.2)
        release-1-0                     (revision: 1.4)
        release-0-4                     (revision: 1.4)

@end example

@cindex Branch numbers
As the output from the @code{status} command shows the branch
number is created by adding a digit at the tail of the revision number
it is based on.  (If @samp{release-1-0} corresponds to revision 1.4, the
branch's revision number will be 1.4.2.  For obscure reasons @sc{cvs} always
gives branches even numbers, starting at 2.
@xref{Revision numbers}).

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Sticky tags
@section Sticky tags
@cindex Sticky tags
@cindex Tags, sticky
@cindex Branches, sticky

@c FIXME: make this stand alone better; many places
@c @xref to this node.
The @samp{-r release-1-0-patches} flag that was given
to @code{checkout} in the previous example
is @dfn{sticky}, that is, it will apply to subsequent commands
in this directory.  If you commit any modifications, they are
committed on the branch.  You can later merge the modifications into
the main trunk.  @xref{Merging}.

You can use the @code{status} command to see what
sticky tags or dates are set:

@c FIXME: This example needs to stand alone better and it
@c would also better if it didn't use -v which only
@c clutters the output in this context.
@example
$ vi driver.c   # @r{Fix the bugs}
$ cvs commit -m "Fixed initialization bug" driver.c
Checking in driver.c;
/usr/local/cvsroot/yoyodyne/tc/driver.c,v  <--  driver.c
new revision: 1.7.2.1; previous revision: 1.7
done
$ cvs status -v driver.c
===================================================================
File: driver.c          Status: Up-to-date

    Version:            1.7.2.1 Sat Dec  5 19:35:03 1992
    RCS Version:        1.7.2.1 /usr/local/cvsroot/yoyodyne/tc/driver.c,v
    Sticky Tag:         release-1-0-patches (branch: 1.7.2)
    Sticky Date:        (none)
    Sticky Options:     (none)

    Existing Tags:
        release-1-0-patches             (branch: 1.7.2)
        release-1-0                     (revision: 1.7)

@end example

@cindex Resetting sticky tags
@cindex Sticky tags, resetting
@cindex Deleting sticky tags
The sticky tags will remain on your working files until
you delete them with @samp{cvs update -A}.  The
@samp{-A} option retrieves the version of the file from
the head of the trunk, and forgets any sticky tags,
dates, or options.

@c Is the fact that CVS works this way a bug or a
@c feature?  If a feature, describe how you would use
@c it to do something useful.
Sticky tags are not just for branches.  If you check
out a certain revision (such as 1.4) it will also
become sticky.  Subsequent @samp{cvs update} will not
retrieve the latest revision until you reset the tag
with @samp{cvs update -A}.  Likewise, use of the
@samp{-D} option to @code{update} or @code{checkout}
sets a @dfn{sticky date}, which, similarly, causes that
date to be used for future retrievals.

@cindex Restoring old version of removed file
@cindex Resurrecting old version of dead file
Many times you will want to retrieve an old version of
a file without setting a sticky tag.  The way to do
that is with the @samp{-p} option to @code{checkout} or
@code{update}, which sends the contents of the file to
standard output.  For example, suppose you have a file
named @file{file1} which existed as revision 1.1, and
you then removed it (thus adding a dead revision 1.2).
Now suppose you want to add it again, with the same
contents it had previously.  Here is how to do it:

@example
$ cvs update -p -r 1.1 file1 >file1
===================================================================
Checking out file1
RCS:  /tmp/cvs-sanity/cvsroot/first-dir/Attic/file1,v
VERS: 1.1
***************
$ cvs add file1
cvs add: version 1.2 of `file1' will be resurrected
cvs add: use 'cvs commit' to add this file permanently
$ cvs commit -m test
Checking in file1;
/tmp/cvs-sanity/cvsroot/first-dir/file1,v  <--  file1
new revision: 1.3; previous revision: 1.2
done
$ 
@end example

@c ---------------------------------------------------------------------
@node Merging
@chapter Merging
@cindex Merging
@cindex Copying changes
@cindex Branches, copying changes between
@cindex Changes, copying between branches
@cindex Modifications, copying between branches

You can include the changes made between any two
revisions into your working copy, by @dfn{merging}.
You can then commit that revision, and thus effectively
copy the changes onto another branch.

@menu
* Merging a branch::            Merging an entire branch
* Merging more than once::      Merging from a branch several times
* Merging two revisions::       Merging differences between two revisions
@end menu

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Merging a branch
@section Merging an entire branch
@cindex Merging a branch
@cindex -j (merging branches)

You can merge changes made on a branch into your working copy by giving
the @samp{-j @var{branch}} flag to the @code{update} command.  With one
@samp{-j @var{branch}} option it merges the changes made between the
point where the branch forked and newest revision on that branch (into
your working copy).

@cindex Join
The @samp{-j} stands for ``join''.

@cindex Branch merge example
@cindex Example, branch merge
@cindex Merge, branch example
Consider this revision tree:

@example
+-----+    +-----+    +-----+    +-----+
! 1.1 !----! 1.2 !----! 1.3 !----! 1.4 !      <- The main trunk
+-----+    +-----+    +-----+    +-----+
                !
                !
                !   +---------+    +---------+
Branch R1fix -> +---! 1.2.2.1 !----! 1.2.2.2 !
                    +---------+    +---------+
@end example

@noindent
The branch 1.2.2 has been given the tag (symbolic name) @samp{R1fix}.  The
following example assumes that the module @samp{mod} contains only one
file, @file{m.c}.

@example
$ cvs checkout mod               # @r{Retrieve the latest revision, 1.4}

$ cvs update -j R1fix m.c        # @r{Merge all changes made on the branch,}
                                 # @r{i.e. the changes between revision 1.2}
                                 # @r{and 1.2.2.2, into your working copy}
                                 # @r{of the file.}

$ cvs commit -m "Included R1fix" # @r{Create revision 1.5.}
@end example

A conflict can result from a merge operation.  If that
happens, you should resolve it before committing the
new revision.  @xref{Conflicts example}.

The @code{checkout} command also supports the @samp{-j @var{branch}} flag.  The
same effect as above could be achieved with this:

@example
$ cvs checkout -j R1fix mod
$ cvs commit -m "Included R1fix"
@end example

@node Merging more than once
@section Merging from a branch several times

Continuing our example, the revision tree now looks
like this:

@example
+-----+    +-----+    +-----+    +-----+    +-----+
! 1.1 !----! 1.2 !----! 1.3 !----! 1.4 !----! 1.5 !      <- The main trunk
+-----+    +-----+    +-----+    +-----+    +-----+
                !                           *
                !                          *
                !   +---------+    +---------+
Branch R1fix -> +---! 1.2.2.1 !----! 1.2.2.2 !
                    +---------+    +---------+
@end example

where the starred line represents the merge from the
@samp{R1fix} branch to the main trunk, as just
discussed.

Now suppose that development continues on the
@samp{R1fix} branch:

@example
+-----+    +-----+    +-----+    +-----+    +-----+
! 1.1 !----! 1.2 !----! 1.3 !----! 1.4 !----! 1.5 !      <- The main trunk
+-----+    +-----+    +-----+    +-----+    +-----+
                !                           *
                !                          *
                !   +---------+    +---------+    +---------+
Branch R1fix -> +---! 1.2.2.1 !----! 1.2.2.2 !----! 1.2.2.3 !
                    +---------+    +---------+    +---------+
@end example

and then you want to merge those new changes onto the
main trunk.  If you just use the @code{cvs update -j
R1fix m.c} command again, @sc{cvs} will attempt to
merge again the changes which you have already merged,
which can have undesirable side effects.

So instead you need to specify that you only want to
merge the changes on the branch which have not yet been
merged into the trunk.  To do that you specify two
@samp{-j} options, and @sc{cvs} merges the changes from
the first revision to the second revision.  For
example, in this case the simplest way would be

@example
cvs update -j 1.2.2.2 -j R1fix m.c    # @r{Merge changes from 1.2.2.2 to the}
                                      # @r{head of the R1fix branch}
@end example

The problem with this is that you need to specify the
1.2.2.2 revision manually.  A slightly better approach
might be to use the date the last merge was done:

@example
cvs update -j R1fix:yesterday -j R1fix m.c
@end example

Better yet, tag the R1fix branch after every merge into
the trunk, and then use that tag for subsequent merges:

@example
cvs update -j merged_from_R1fix_to_trunk -j R1fix m.c
@end example

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Merging two revisions
@section Merging differences between any two revisions
@cindex Merging two revisions
@cindex Revisions, merging differences between
@cindex Differences, merging

With two @samp{-j @var{revision}} flags, the @code{update}
(and @code{checkout}) command can merge the differences
between any two revisions into your working file.

@cindex Undoing a change
@cindex Removing a change
@example
$ cvs update -j 1.5 -j 1.3 backend.c
@end example

@noindent
will @emph{remove} all changes made between revision
1.3 and 1.5.  Note the order of the revisions!

If you try to use this option when operating on
multiple files, remember that the numeric revisions will
probably be very different between the various files
that make up a module.  You almost always use symbolic
tags rather than revision numbers when operating on
multiple files.

@c ---------------------------------------------------------------------
@node Recursive behavior
@chapter Recursive behavior
@cindex Recursive (directory descending)
@cindex Directory, descending
@cindex Descending directories
@cindex Subdirectories

Almost all of the subcommands of @sc{cvs} work
recursively when you specify a directory as an
argument.  For instance, consider this directory
structure:

@example
      @code{$HOME}
        |
        +--@t{tc}
        |   |
            +--@t{CVS}
            |      (internal @sc{cvs} files)
            +--@t{Makefile}
            +--@t{backend.c}
            +--@t{driver.c}
            +--@t{frontend.c}
            +--@t{parser.c}
            +--@t{man}
            |    |
            |    +--@t{CVS}
            |    |  (internal @sc{cvs} files)
            |    +--@t{tc.1}
            |     
            +--@t{testing}
                 |
                 +--@t{CVS}
                 |  (internal @sc{cvs} files)
                 +--@t{testpgm.t}
                 +--@t{test2.t}
@end example

@noindent
If @file{tc} is the current working directory, the
following is true:

@itemize @bullet
@item
@samp{cvs update testing} is equivalent to @samp{cvs
update testing/testpgm.t testing/test2.t}

@item
@samp{cvs update testing man} updates all files in the
subdirectories 

@item
@samp{cvs update .} or just @samp{cvs update} updates
all files in the @code{tc} module
@end itemize

If no arguments are given to @code{update} it will
update all files in the current working directory and
all its subdirectories.  In other words, @file{.} is a
default argument to @code{update}.  This is also true
for most of the @sc{cvs} subcommands, not only the
@code{update} command.

The recursive behavior of the @sc{cvs} subcommands can be
turned off with the @samp{-l} option.

@example
$ cvs update -l         # @r{Don't update files in subdirectories}
@end example

@c ---------------------------------------------------------------------
@node Adding files
@chapter Adding files to a module
@cindex Adding files

To add a new file to a module, follow these steps.

@itemize @bullet
@item
You must have a working copy of the module.
@xref{Getting the source}.

@item
Create the new file inside your working copy of the module.

@item
Use @samp{cvs add @var{filename}} to tell @sc{cvs} that you
want to version control the file.

@item
Use @samp{cvs commit @var{filename}} to actually check
in the file into the repository.  Other developers
cannot see the file until you perform this step.

@item
If the file contains binary data it might be necessary
to change the default keyword substitution.
@xref{Keyword substitution}.  @xref{admin examples}.
@end itemize

You can also use the @code{add} command to add a new
directory inside a module.

Unlike most other commands, the @code{add} command is
not recursive.  You cannot even type @samp{cvs add
foo/bar}!  Instead, you have to

@example
$ cd foo
$ cvs add bar
@end example

@xref{add}, for a more complete description of the @code{add}
command.

@c ---------------------------------------------------------------------
@node Removing files
@chapter Removing files from a module
@cindex Removing files
@cindex Deleting files

Modules change.  New files are added, and old files
disappear.  Still, you want to be able to retrieve an
exact copy of old releases of the module.

Here is what you can do to remove a file from a module,
but remain able to retrieve old revisions:

@itemize @bullet
@item
Make sure that you have not made any uncommitted
modifications to the file.  @xref{Viewing differences},
for one way to do that.  You can also use the
@code{status} or @code{update} command.  If you remove
the file without committing your changes, you will of
course not be able to retrieve the file as it was
immediately before you deleted it.

@item
Remove the file from your working copy of the module.
You can for instance use @code{rm}.

@item
Use @samp{cvs remove @var{filename}} to tell @sc{cvs} that
you really want to delete the file.

@item
Use @samp{cvs commit @var{filename}} to actually
perform the removal of the file from the repository.
@end itemize

When you commit the removal of the file, @sc{cvs}
records the fact that the file no longer exists.  It is
possible for a file to exist on only some branches and
not on others, or to re-add another file with the same
name later.  CVS will correctly create or not create
the file, based on the @samp{-r} and @samp{-D} options
specified to @code{checkout} or @code{update}.

@cindex Remove (subcommand)
@deffn Command {cvs remove} [@code{-lR}] files @dots{}

Schedule file(s) to be removed from the repository
(files which have not already been removed from the
working directory are not processed).  This command
does not actually remove the file from the repository
until you commit the removal.  The @samp{-R} option
(the default) specifies that it will recurse into
subdirectories; @samp{-l} specifies that it will not.
@end deffn

Here is an example of removing several files:

@example
$ cd test
$ rm ?.c
$ cvs remove
cvs remove: Removing .
cvs remove: scheduling a.c for removal
cvs remove: scheduling b.c for removal
cvs remove: use 'cvs commit' to remove these files permanently
$ cvs ci -m "Removed unneeded files"
cvs commit: Examining .
cvs commit: Committing .
@end example

If you change your mind you can easily resurrect the
file before you commit it, using the @code{add}
command.

@example
$ ls
CVS   ja.h  oj.c
$ rm oj.c
$ cvs remove oj.c
cvs remove: scheduling oj.c for removal
cvs remove: use 'cvs commit' to remove this file permanently
$ cvs add oj.c
U oj.c
cvs add: oj.c, version 1.1.1.1, resurrected
@end example

If you realize your mistake before you run the
@code{remove} command you can use @code{update} to
resurrect the file:

@example
$ rm oj.c
$ cvs update oj.c
cvs update: warning: oj.c was lost
U oj.c
@end example

@c ---------------------------------------------------------------------
@node Tracking sources
@chapter Tracking third-party sources
@cindex Third-party sources
@cindex Tracking sources

If you modify a program to better fit your site, you
probably want to include your modifications when the next
release of the program arrives.  @sc{cvs} can help you with
this task.

@cindex Vendor
@cindex Vendor branch
@cindex Branch, vendor-
In the terminology used in @sc{cvs}, the supplier of the
program is called a @dfn{vendor}.  The unmodified
distribution from the vendor is checked in on its own
branch, the @dfn{vendor branch}.  @sc{cvs} reserves branch
1.1.1 for this use.

When you modify the source and commit it, your revision
will end up on the main trunk.  When a new release is
made by the vendor, you commit it on the vendor branch
and copy the modifications onto the main trunk.

Use the @code{import} command to create and update
the vendor branch.  After a successful @code{import}
the vendor branch is made the `head' revision, so
anyone that checks out a copy of the file gets that
revision.  When a local modification is committed it is
placed on the main trunk, and made the `head'
revision.

@menu
* First import::                Importing a module for the first time
* Update imports::              Updating a module with the import command
@end menu

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node First import
@section Importing a module for the first time
@cindex Importing modules

Use the @code{import} command to check in the sources
for the first time.  When you use the @code{import}
command to track third-party sources, the @dfn{vendor
tag} and @dfn{release tags} are useful.  The
@dfn{vendor tag} is a symbolic name for the branch
(which is always 1.1.1, unless you use the @samp{-b
@var{branch}} flag---@xref{import options}).  The
@dfn{release tags} are symbolic names for a particular
release, such as @samp{FSF_0_04}.

@cindex Wdiff (import example)
Suppose you use @code{wdiff} (a variant of @code{diff}
that ignores changes that only involve whitespace), and
are going to make private modifications that you want
to be able to use even when new releases are made in
the future.  You start by importing the source to your
repository:

@example
$ tar xfz wdiff-0.04.tar.gz
$ cd wdiff-0.04
$ cvs import -m "Import of FSF v. 0.04" fsf/wdiff FSF_DIST WDIFF_0_04
@end example

The vendor tag is named @samp{FSF_DIST} in the above
example, and the only release tag assigned is
@samp{WDIFF_0_04}.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Update imports
@section Updating a module with the import command

When a new release of the source arrives, you import it into the
repository with the same @code{import} command that you used to set up
the repository in the first place.  The only difference is that you
specify a different release tag this time.

@example
$ tar xfz wdiff-0.05.tar.gz
$ cd wdiff-0.05
$ cvs import -m "Import of FSF v. 0.05" fsf/wdiff FSF_DIST WDIFF_0_05
@end example

For files that have not been modified locally, the newly created
revision becomes the head revision.  If you have made local
changes, @code{import} will warn you that you must merge the changes
into the main trunk, and tell you to use @samp{checkout -j} to do so.

@example
$ cvs checkout -jFSF_DIST:yesterday -jFSF_DIST wdiff
@end example

@noindent
The above command will check out the latest revision of
@samp{wdiff}, merging the changes made on the vendor branch @samp{FSF_DIST}
since yesterday into the working copy.  If any conflicts arise during
the merge they should be resolved in the normal way (@pxref{Conflicts
example}).  Then, the modified files may be committed.

Using a date, as suggested above, assumes that you do
not import more than one release of a product per
day. If you do, you can always use something like this
instead:

@example
$ cvs checkout -jWDIFF_0_04 -jWDIFF_0_05 wdiff
@end example

@noindent
In this case, the two above commands are equivalent.

@c ---------------------------------------------------------------------
@node Moving files
@chapter Moving and renaming files
@cindex Moving files
@cindex Renaming files
@cindex Files, moving

Moving files to a different directory or renaming them
is not difficult, but some of the ways in which this
works may be non-obvious.  (Moving or renaming a
directory is even harder.  @xref{Moving directories}).

The examples below assume that the file @var{old} is renamed to
@var{new}.

@menu
* Outside::                     The normal way to Rename
* Inside::                      A tricky, alternative way
* Rename by copying::           Another tricky, alternative way
@end menu

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Outside
@section The Normal way to Rename

The normal way to move a file is to copy @var{old} to
@var{new}, and then issue the normal @sc{cvs} commands
to remove @var{old} from the repository, and add
@var{new} to it.  (Both @var{old} and @var{new} could
contain relative paths, for example @file{foo/bar.c}).

@example
$ mv @var{old} @var{new}
$ cvs remove @var{old}
$ cvs add @var{new} 
$ cvs commit -m "Renamed @var{old} to @var{new}" @var{old} @var{new}
@end example

This is the simplest way to move a file, it is not
error-prone, and it preserves the history of what was
done.  Note that to access the history of the file you
must specify the old or the new name, depending on what
portion of the history you are accessing.  For example,
@code{cvs log @var{old}} will give the log up until the
time of the rename.

When @var{new} is committed its revision numbers will
start at 1.0 again, so if that bothers you, use the
@samp{-r rev} option to commit (@pxref{commit options})

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Inside
@section Moving the history file

This method is more dangerous, since it involves moving
files inside the repository.  Read this entire section
before trying it out!

@example
$ cd $CVSROOT/@var{module}
$ mv @var{old},v @var{new},v
@end example

@noindent
Advantages:

@itemize @bullet
@item
The log of changes is maintained intact.

@item
The revision numbers are not affected.
@end itemize

@noindent
Disadvantages:

@itemize @bullet
@item
Old releases of the module cannot easily be fetched from the
repository.  (The file will show up as @var{new} even
in revisions from the time before it was renamed).

@item
There is no log information of when the file was renamed.

@item
Nasty things might happen if someone accesses the history file
while you are moving it.  Make sure no one else runs any of the @sc{cvs}
commands while you move it.
@end itemize

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Rename by copying
@section Copying the history file

This way also involves direct modifications to the
repository.  It is safe, but not without drawbacks.

@example
# @r{Copy the @sc{rcs} file inside the repository}
$ cd $CVSROOT/@var{module}
$ cp @var{old},v @var{new},v
# @r{Remove the old file}
$ cd ~/@var{module}
$ rm @var{old}
$ cvs remove @var{old}
$ cvs commit @var{old}
# @r{Remove all tags from @var{new}}
$ cvs update @var{new}
$ cvs log @var{new}             # @r{Remember the tag names}
$ cvs tag -d @var{tag1}
$ cvs tag -d @var{tag2}
@dots{}
@end example

By removing the tags you will be able to check out old
revisions of the module.

@noindent
Advantages:

@itemize @bullet
@item
@c FIXME: Is this true about -D now that we have death
@c support?  See 5B.3 in the FAQ.
Checking out old revisions works correctly, as long as
you use @samp{-r@var{tag}} and not @samp{-D@var{date}}
to retrieve the revisions.

@item
The log of changes is maintained intact.

@item
The revision numbers are not affected.
@end itemize

@noindent
Disadvantages:

@itemize @bullet
@item
You cannot easily see the history of the file across the rename.

@item
Unless you use the @samp{-r rev} (@pxref{commit
options}) flag when @var{new} is committed its revision
numbers will start at 1.0 again.
@end itemize

@c ---------------------------------------------------------------------
@node Moving directories
@chapter Moving and renaming directories
@cindex Moving directories
@cindex Renaming directories
@cindex Directories, moving

If you want to be able to retrieve old versions of the
module, you must move each file in the directory
with the @sc{cvs} commands.  @xref{Outside}.  The old, empty
directory will remain inside the repository, but it
will not appear in your workspace when you check out
the module in the future.
@c -- rephrase

If you really want to rename or delete a directory, you
can do it like this:

@enumerate
@item
Inform everyone who has a copy of the module that the
directory will be renamed.  They should commit all
their changes, and remove their working copies of the
module, before you take the steps below.

@item
Rename the directory inside the repository.

@example
$ cd $CVSROOT/@var{module}
$ mv @var{old-dir} @var{new-dir}
@end example

@item
Fix the @sc{cvs} administrative files, if necessary (for
instance if you renamed an entire module).

@item
Tell everyone that they can check out the module and continue
working.

@end enumerate

If someone had a working copy of the module the @sc{cvs} commands will
cease to work for him, until he removes the directory
that disappeared inside the repository.

It is almost always better to move the files in the
directory instead of moving the directory.  If you move the
directory you are unlikely to be able to retrieve old
releases correctly, since they probably depend on the
name of the directories.

@c ---------------------------------------------------------------------
@node History browsing
@chapter History browsing
@cindex History browsing
@cindex Traceability
@cindex Isolation

@ignore
@c This is too long for an introduction (goal is
@c one 20x80 character screen), and also mixes up a
@c variety of issues (parallel development, history,
@c maybe even touches on process control).

@c -- @quote{To lose ones history is to lose ones soul.}
@c -- ///
@c -- ///Those who cannot remember the past are condemned to repeat it.
@c -- ///               -- George Santayana
@c -- ///

@sc{cvs} tries to make it easy for a group of people to work
together.  This is done in two ways:

@itemize @bullet
@item
Isolation---You have your own working copy of the
source.  You are not affected by modifications made by
others until you decide to incorporate those changes
(via the @code{update} command---@pxref{update}).

@item 
Traceability---When something has changed, you can
always see @emph{exactly} what changed.
@end itemize

There are several features of @sc{cvs} that together lead
to traceability:

@itemize @bullet
@item
Each revision of a file has an accompanying log
message.

@item
All commits are optionally logged to a central history
database.

@item
Logging information can be sent to a user-defined
program (@pxref{loginfo}).
@end itemize

@c -- More text here.

This chapter should talk about the history file, the
@code{log} command, the usefulness of ChangeLogs
even when you run @sc{cvs}, and things like that.

@end ignore

@c kind of lame, in a lot of ways the above text inside
@c the @ignore motivates this chapter better
Once you have used @sc{cvs} to store a version control
history---what files have changed when, how, and by
whom, there are a variety of mechanisms for looking
through the history.

@menu
* log messages::                Log messages
* history database::            The history database
* user-defined logging::        User-defined logging
* annotate::                    What revision modified each line of a file?
@end menu

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node log messages
@section Log messages

@c FIXME: @xref to place where we talk about how to
@c specify message to commit.
Whenever you commit a file you specify a log message.

@c FIXME: bring the information here, and get rid of or
@c greatly shrink the "log" node.
To look through the log messages which have been
specified for every revision which has been committed,
use the @code{cvs log} command (@pxref{log}).

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node history database
@section The history database

@c FIXME: bring the information from the history file
@c and history nodes here.  Rewrite it to be motivated
@c better (start out by clearly explaining what gets
@c logged in history, for example).
You can use the history file (@pxref{history file}) to
log various @sc{cvs} actions.  To retrieve the
information from the history file, use the @code{cvs
history} command (@pxref{history}).

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node user-defined logging
@section User-defined logging

@c FIXME: should probably also mention the fact the -l
@c global option can disable most of the mechanisms
@c discussed here (why?  What is the -l global option for?).
@c
@c FIXME: probably should centralize this information
@c here, at least to some extent.  Maybe by moving the
@c loginfo, etc., nodes here and replacing
@c the "user-defined logging" node with one node for
@c each method.
You can customize @sc{cvs} to log various kinds of
actions, in whatever manner you choose.  These
mechanisms operate by executing a script at various
times.  The script might append a message to a file
listing the information and the programmer who created
it, or send mail to a group of developers, or, perhaps,
post a message to a particular newsgroup.  To log
commits, use the @file{loginfo} file (@pxref{loginfo}).
@c FIXME: What is difference between doing it in the
@c modules file and using loginfo/taginfo?  Why should
@c user use one or the other?
To log commits, checkouts, exports, and tags,
respectively, you can also use the @samp{-i},
@samp{-o}, @samp{-e}, and @samp{-t} options in the
modules file.  For a more flexible way of giving
notifications to various users, which requires less in
the way of keeping centralized scripts up to date, use
the @code{cvs watch add} command (@pxref{Getting
Notified}); this command is useful even if you are not
using @code{cvs watch on}.

@cindex taginfo
The @file{taginfo} file defines programs to execute
when someone executes a @code{tag} or @code{rtag}
command.  The @file{taginfo} file has the standard form
for administrative files (@pxref{Administrative
files}), where each line is a regular expression
followed by a command to execute.  The arguments passed
to the command are, in order, the @var{tagname},
@var{operation} (@code{add} for @code{tag},
@code{mov} for @code{tag -F}, and @code{del} for
@code{tag -d}), @var{repository}, and any remaining are
pairs of @var{filename} @var{revision}.  A non-zero
exit of the filter program will cause the tag to be
aborted.

@node annotate
@section Annotate command
@cindex annotate (subcommand)

@deffn Command {cvs annotate} [@code{-l}] files @dots{}

For each file in @var{files}, print the head revision
of the trunk, together with information on the last
modification for each line.  The @code{-l} option means
to process the local directory only, not to recurse
(@pxref{Common options}).  For example:

@example
$ cvs annotate ssfile
Annotations for ssfile
***************
1.1          (mary     27-Mar-96): ssfile line 1
1.2          (joe      28-Mar-96): ssfile line 2
@end example

The file @file{ssfile} currently contains two lines.
The @code{ssfile line 1} line was checked in by
@code{mary} on March 27.  Then, on March 28, @code{joe}
added a line @code{ssfile line 2}, without modifying
the @code{ssfile line 1} line.  This report doesn't
tell you anything about lines which have been deleted
or replaced; you need to use @code{cvs diff} for that
(@pxref{diff}).

@end deffn

@c ---------------------------------------------------------------------
@node Keyword substitution
@chapter Keyword substitution
@cindex Keyword substitution
@cindex Keyword expansion
@cindex Identifying files

@comment   Be careful when editing this chapter.
@comment   Remember that this file is kept under
@comment   version control, so we must not accidentally
@comment   include a valid keyword in the running text.

As long as you edit source files inside your working
copy of a module you can always find out the state of
your files via @samp{cvs status} and @samp{cvs log}.
But as soon as you export the files from your
development environment it becomes harder to identify
which revisions they are.

@sc{Rcs} uses a mechanism known as @dfn{keyword
substitution} (or @dfn{keyword expansion}) to help
identifying the files.  Embedded strings of the form
@code{$@var{keyword}$} and
@code{$@var{keyword}:@dots{}$} in a file are replaced
with strings of the form
@code{$@var{keyword}:@var{value}$} whenever you obtain
a new revision of the file.

@menu
* Keyword list::                RCS Keywords
* Using keywords::              Using keywords
* Avoiding substitution::       Avoiding substitution
* Substitution modes::          Substitution modes
* Log keyword::                 Problems with the $@asis{}Log$ keyword.
@end menu

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Keyword list
@section RCS Keywords
@cindex RCS keywords

This is a list of the keywords that @sc{rcs} currently
(in release 5.6.0.1) supports:

@table @code
@cindex Author keyword
@item $@asis{Author}$
The login name of the user who checked in the revision.

@cindex Date keyword
@item $@asis{Date}$
The date and time (UTC) the revision was checked in.

@cindex Header keyword
@item $@asis{Header}$
A standard header containing the full pathname of the
@sc{rcs} file, the revision number, the date (UTC), the
author, the state, and the locker (if locked).  Files
will normally never be locked when you use @sc{cvs}.

@cindex Id keyword
@item $@asis{Id}$
Same as @code{$@asis{Header}$}, except that the @sc{rcs}
filename is without a path.

@cindex Locker keyword
@item $@asis{Locker}$
The login name of the user who locked the revision
(empty if not locked, and thus almost always useless
when you are using @sc{cvs}).

@cindex Log keyword
@item $@asis{Log}$
The log message supplied during commit, preceded by a
header containing the @sc{rcs} filename, the revision
number, the author, and the date (UTC).  Existing log
messages are @emph{not} replaced.  Instead, the new log
message is inserted after @code{$@asis{Log:@dots{}}$}.
Each new line is prefixed with a @dfn{comment leader}
which @sc{rcs} guesses from the file name extension.
It can be changed with @code{cvs admin -c}.
@xref{admin options}.  This keyword is useful for
accumulating a complete change log in a source file,
but for several reasons it can be problematic.
@xref{Log keyword}.

@cindex RCSfile keyword
@item $@asis{RCSfile}$
The name of the RCS file without a path.

@cindex Revision keyword
@item $@asis{Revision}$
The revision number assigned to the revision.

@cindex Source keyword
@item $@asis{Source}$
The full pathname of the RCS file.

@cindex State keyword
@item $@asis{State}$
The state assigned to the revision.  States can be
assigned with @code{cvs admin -s}---@xref{admin options}.

@end table

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Using keywords
@section Using keywords

To include a keyword string you simply include the
relevant text string, such as @code{$@asis{Id}$}, inside the
file, and commit the file.  @sc{cvs} will automatically
expand the string as part of the commit operation.

@need 800
It is common to embed @code{$@asis{}Id$} string in the
C source code.  This example shows the first few lines
of a typical file, after keyword substitution has been
performed:

@example
static char *rcsid="$@asis{}Id: samp.c,v 1.5 1993/10/19 14:57:32 ceder Exp $";
/* @r{The following lines will prevent @code{gcc} version 2.@var{x}}
   @r{from issuing an "unused variable" warning}. */
#if __GNUC__ == 2
#define USE(var) static void * use_##var = (&use_##var, (void *) &var) 
USE (rcsid);
#endif
@end example

Even though a clever optimizing compiler could remove
the unused variable @code{rcsid}, most compilers tend
to include the string in the binary.  Some compilers
have a @code{#pragma} directive to include literal text
in the binary.

@cindex Ident (shell command)
The @code{ident} command (which is part of the @sc{rcs}
package) can be used to extract keywords and their
values from a file.  This can be handy for text files,
but it is even more useful for extracting keywords from
binary files.

@example
$ ident samp.c
samp.c:
     $@asis{}Id: samp.c,v 1.5 1993/10/19 14:57:32 ceder Exp $
$ gcc samp.c
$ ident a.out
a.out:
     $@asis{}Id: samp.c,v 1.5 1993/10/19 14:57:32 ceder Exp $
@end example

@cindex What (shell command)
S@sc{ccs} is another popular revision control system.
It has a command, @code{what}, which is very similar to
@code{ident} and used for the same purpose.  Many sites
without @sc{rcs} have @sc{sccs}.  Since @code{what}
looks for the character sequence @code{@@(#)} it is
easy to include keywords that are detected by either
command.  Simply prefix the @sc{rcs} keyword with the
magic @sc{sccs} phrase, like this:

@example
static char *id="@@(#) $@asis{}Id: ab.c,v 1.5 1993/10/19 14:57:32 ceder Exp $";
@end example

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Avoiding substitution
@section Avoiding substitution

Keyword substitution has its disadvantages.  Sometimes
you might want the literal text string
@samp{$@asis{}Author$} to appear inside a file without
@sc{rcs} interpreting it as a keyword and expanding it
into something like @samp{$@asis{}Author: ceder $}.  

There is unfortunately no way to selectively turn off
keyword substitution.  You can use @samp{-ko}
(@pxref{Substitution modes}) to turn off keyword
substitution entirely.

In many cases you can avoid using @sc{rcs} keywords in
the source, even though they appear in the final
product.  For example, the source for this manual
contains @samp{$@@asis@{@}Author$} whenever the text
@samp{$@asis{}Author$} should appear.  In @code{nroff}
and @code{troff} you can embed the null-character
@code{\&} inside the keyword for a similar effect.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Substitution modes
@section Substitution modes
@cindex -k (RCS kflags)
@cindex Kflag

@c FIXME: This could be made more coherent, by expanding it
@c with more examples or something.
Each file has a stored default substitution mode, and
each working directory copy of a file also has a
substitution mode.  The former is set by the @samp{-k}
option to @code{cvs add} and @code{cvs admin}; the
latter is set by the -k or -A options to @code{cvs
checkout} or @code{cvs update}.  @code{cvs diff} also
has a @samp{-k} option.  For some examples,
@xref{Binary files}.

The modes available are:

@table @samp
@item -kkv
Generate keyword strings using the default form, e.g.
@code{$@asis{}Revision: 5.7 $} for the @code{Revision}
keyword.

@item -kkvl
Like @samp{-kkv}, except that a locker's name is always
inserted if the given revision is currently locked.
This option is normally not useful when @sc{cvs} is used.

@item -kk
Generate only keyword names in keyword strings; omit
their values.  For example, for the @code{Revision}
keyword, generate the string @code{$@asis{}Revision$}
instead of @code{$@asis{}Revision: 5.7 $}.  This option
is useful to ignore differences due to keyword
substitution when comparing different revisions of a
file.

@item -ko
Generate the old keyword string, present in the working
file just before it was checked in.  For example, for
the @code{Revision} keyword, generate the string
@code{$@asis{}Revision: 1.1 $} instead of
@code{$@asis{}Revision: 5.7 $} if that is how the
string appeared when the file was checked in.

@item -kb
Like @samp{-ko}, but also inhibit conversion of line
endings between the canonical form in which they are
stored in the repository (linefeed only), and the form
appropriate to the operating system in use on the
client.  For systems, like unix, which use linefeed
only to terminate lines, this is the same as
@samp{-ko}.  For more information on binary files, see
@ref{Binary files}.

@item -kv
Generate only keyword values for keyword strings.  For
example, for the @code{Revision} keyword, generate the string
@code{5.7} instead of @code{$@asis{}Revision: 5.7 $}.
This can help generate files in programming languages
where it is hard to strip keyword delimiters like
@code{$@asis{}Revision: $} from a string.  However,
further keyword substitution cannot be performed once
the keyword names are removed, so this option should be
used with care.

One often would like to use @samp{-kv} with @code{cvs
export}---@pxref{export}.  But be aware that doesn't
handle an export containing binary files correctly.

@end table

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Log keyword
@section Problems with the $@asis{}Log$ keyword.

The @code{$@asis{}Log$} keyword is somewhat
controversial.  As long as you are working on your
development system the information is easily accessible
even if you do not use the @code{$@asis{}Log$}
keyword---just do a @code{cvs log}.  Once you export
the file the history information might be useless
anyhow.

A more serious concern is that @sc{rcs} is not good at
handling @code{$@asis{}Log$} entries when a branch is
merged onto the main trunk.  Conflicts often result
from the merging operation.

People also tend to "fix" the log entries in the file
(correcting spelling mistakes and maybe even factual
errors).  If that is done the information from
@code{cvs log} will not be consistent with the
information inside the file.  This may or may not be a
problem in real life.

It has been suggested that the @code{$@asis{}Log$}
keyword should be inserted @emph{last} in the file, and
not in the files header, if it is to be used at all.
That way the long list of change messages will not
interfere with everyday source file browsing.

@c ---------------------------------------------------------------------
@node Binary files
@chapter Handling binary files
@cindex Binary files

There are two issues with using @sc{cvs} to store
binary files.  The first is that @sc{cvs} by default
convert line endings between the canonical form in
which they are stored in the repository (linefeed
only), and the form appropriate to the operating system
in use on the client (for example, carriage return
followed by line feed for Windows NT).

The second is that a binary file might happen to
contain data which looks like a keyword (@pxref{Keyword
substitution}), so keyword expansion must be turned
off.

The @samp{-kb} option available with some @sc{cvs}
commands insures that neither line ending conversion
nor keyword expansion will be done.  If you are using
an old version of @sc{rcs} without this option, and you
are using an operating system, such as unix, which
terminates lines with linefeeds only, you can use
@samp{-ko} instead; if you are on another operating
system, upgrade to a version of @sc{rcs}, such as 5.7
or later, which supports @samp{-kb}.

Here is an example of how you can create a new file
using the @samp{-kb} flag:

@example
$ echo '$@asis{}Id$' > kotest
$ cvs add -kb -m"A test file" kotest
$ cvs ci -m"First checkin; contains a keyword" kotest
@end example

If a file accidentally gets added without @samp{-kb},
one can use the @code{cvs admin} command to recover.
For example:

@example
$ echo '$@asis{}Id$' > kotest
$ cvs add -m"A test file" kotest
$ cvs ci -m"First checkin; contains a keyword" kotest
$ cvs admin -kb kotest
$ cvs update -A kotest
@end example

When you check in the file @file{kotest} the keywords
are expanded.  (Try the above example, and do a
@code{cat kotest} after every command).  The @code{cvs
admin -kb} command sets the default keyword
substitution method for this file, but it does not
alter the working copy of the file that you have.  The
easiest way to get the unexpanded version of
@file{kotest} is @code{cvs update -A}.

@c ---------------------------------------------------------------------
@node Revision management
@chapter Revision management
@cindex Revision management

@c -- This chapter could be expanded a lot.
@c -- Experiences are very welcome!

If you have read this far, you probably have a pretty
good grasp on what @sc{cvs} can do for you.  This
chapter talks a little about things that you still have
to decide.

If you are doing development on your own using @sc{cvs}
you could probably skip this chapter.  The questions
this chapter takes up become more important when more
than one person is working in a repository.

@menu
* When to commit::              Some discussion on the subject
@end menu

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node When to commit
@section When to commit?
@cindex When to commit
@cindex Commit, when to
@cindex Policy

Your group should decide which policy to use regarding
commits.  Several policies are possible, and as your
experience with @sc{cvs} grows you will probably find
out what works for you.

If you commit files too quickly you might commit files
that do not even compile.  If your partner updates his
working sources to include your buggy file, he will be
unable to compile the code.  On the other hand, other
persons will not be able to benefit from the
improvements you make to the code if you commit very
seldom, and conflicts will probably be more common.

It is common to only commit files after making sure
that they can be compiled.  Some sites require that the
files pass a test suite.  Policies like this can be
enforced using the commitinfo file
(@pxref{commitinfo}), but you should think twice before
you enforce such a convention.  By making the
development environment too controlled it might become
too regimented and thus counter-productive to the real
goal, which is to get software written.

@c ---------------------------------------------------------------------
@node Invoking CVS
@appendix Reference manual for CVS commands
@cindex Command reference
@cindex Reference, commands
@cindex Invoking CVS

This appendix describes how to invoke @sc{cvs}, and
describes in detail those subcommands of @sc{cvs} which
are not fully described elsewhere.  To look up a
particular subcommand, see @ref{Index}.

@menu
* Structure::                   Overall structure of CVS commands
* ~/.cvsrc::                    Default options with the ~/.csvrc file
* Global options::              Options you give to the left of cvs_command
* Common options::              Options you give to the right of cvs_command
* add::                         Add a new file/directory to the repository
* admin::                       Administration front end for rcs
* checkout::                    Checkout sources for editing
* commit::                      Check files into the repository
* diff::                        Run diffs between revisions
* export::                      Export sources from CVS, similar to checkout
* history::                     Show status of files and users
* import::                      Import sources into CVS, using vendor branches
* log::                         Print out 'rlog' information for files
* rdiff::                       'patch' format diffs between releases
* release::                     Indicate that a Module is no longer in use
* rtag::                        Add a tag to a module
* status::                      Status info on the revisions
* tag::                         Add a tag to checked out version
* update::                      Bring work tree in sync with repository
@end menu

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Structure
@appendixsec Overall structure of CVS commands
@cindex Structure
@cindex CVS command structure
@cindex Command structure
@cindex Format of CVS commands

The first release of @sc{cvs} consisted of a number of shell-scripts.
Today @sc{cvs} is implemented as a single program that is a front-end
to @sc{rcs} and @code{diff}. The overall format of all
@sc{cvs} commands is:

@example
cvs [ cvs_options ] cvs_command [ command_options ] [ command_args ]
@end example

@table @code
@item cvs
The program that is a front-end to @sc{rcs}.

@item cvs_options
Some options that affect all sub-commands of @sc{cvs}.  These are
described below.

@item cvs_command
One of several different sub-commands.  Some of the commands have
aliases that can be used instead; those aliases are noted in the
reference manual for that command.  There are only two situations
where you may omit @samp{cvs_command}: @samp{cvs -H} elicits a
list of available commands, and @samp{cvs -v} displays version
information on @sc{cvs} itself.

@item command_options
Options that are specific for the command.

@item command_args
Arguments to the commands.
@end table

There is unfortunately some confusion between
@code{cvs_options} and @code{command_options}.
@samp{-l}, when given as a @code{cvs_option}, only
affects some of the commands.  When it is given as a
@code{command_option} is has a different meaning, and
is accepted by more commands.  In other words, do not
take the above categorization too seriously.  Look at
the documentation instead.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node ~/.cvsrc
@appendixsec Default options and the ~/.cvsrc file
@cindex .cvsrc file
@cindex option defaults

There are some @code{command_options} that are used so
often that you might have set up an alias or some other
means to make sure you always specify that option.  One
example (the one that drove the implementation of the
.cvsrc support, actually) is that many people find the
default output of the @samp{diff} command to be very
hard to read, and that either context diffs or unidiffs
are much easier to understand.

The @file{~/.cvsrc} file is a way that you can add
default options to @code{cvs_commands} within cvs,
instead of relying on aliases or other shell scripts.

The format of the @file{~/.cvsrc} file is simple.  The
file is searched for a line that begins with the same
name as the @code{cvs_command} being executed.  If a
match is found, then the remainder of the line is split
up (at whitespace characters) into separate options and
added to the command arguments @emph{before} any
options from the command line.

If a command has two names (e.g., @code{checkout} and
@code{co}), the official name, not necessarily the one
used on the command line, will be used to match against
the file.  So if this is the contents of the user's
@file{~/.cvsrc} file:

@example
log -N
diff -u
update -P
co -P
@end example

@noindent
the command @samp{cvs checkout foo} would have the
@samp{-P} option added to the arguments, as well as
@samp{cvs co foo}.

With the example file above, the output from @samp{cvs
diff foobar} will be in unidiff format.  @samp{cvs diff
-c foobar} will provide context diffs, as usual.
Getting "old" format diffs would be slightly more
complicated, because @code{diff} doesn't have an option
to specify use of the "old" format, so you would need
@samp{cvs -f diff foobar}.

In place of the command name you can use @code{cvs} to
specify global options (@pxref{Global options}).  For
example the following line in @file{.cvsrc}

@example
cvs -z6
@end example

causes @sc{cvs} to use compression level 6

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Global options
@appendixsec Global options
@cindex Options, global
@cindex Global options
@cindex Left-hand options

The available @samp{cvs_options} (that are given to the
left of @samp{cvs_command}) are:

@table @code
@cindex RCSBIN, overriding
@cindex Overriding RCSBIN
@item -b @var{bindir}
Use @var{bindir} as the directory where @sc{rcs} programs are
located.  Overrides the setting of the @code{$RCSBIN} environment
variable and any precompiled directory.  This parameter should be
specified as an absolute pathname.

@cindex CVSROOT, overriding
@cindex Overriding CVSROOT
@item -d @var{cvs_root_directory}
Use @var{cvs_root_directory} as the root directory
pathname of the repository.  Overrides the setting of
the @code{$CVSROOT} environment variable.  @xref{Repository}.

@cindex EDITOR, overriding
@cindex Overriding EDITOR
@item -e @var{editor}
Use @var{editor} to enter revision log information.  Overrides the
setting of the @code{$CVSEDITOR} and @code{$EDITOR} environment variables.

@item -f
Do not read the @file{~/.cvsrc} file.  This
option is most often used because of the
non-orthogonality of the @sc{cvs} option set.  For
example, the @samp{cvs log} option @samp{-N} (turn off
display of tag names) does not have a corresponding
option to turn the display on.  So if you have
@samp{-N} in the @file{~/.cvsrc} entry for @samp{diff},
you may need to use @samp{-f} to show the tag names.
@footnote{Yes, this really should be fixed, and it's
being worked on}

@item -H
Display usage information about the specified @samp{cvs_command}
(but do not actually execute the command).  If you don't specify
a command name, @samp{cvs -H} displays a summary of all the
commands available.

@item -l
Do not log the cvs_command in the command history (but execute it
anyway).  @xref{history}, for information on command history.

@cindex Read-only mode
@item -n
Do not change any files.  Attempt to execute the
@samp{cvs_command}, but only to issue reports; do not remove,
update, or merge any existing files, or create any new files.

@item -Q
Cause the command to be really quiet; the command will only
generate output for serious problems.

@item -q
Cause the command to be somewhat quiet; informational messages,
such as reports of recursion through subdirectories, are
suppressed.

@cindex Read-only files
@item -r
Make new working files files read-only.  Same effect
as if the @code{$CVSREAD} environment variable is set
(@pxref{Environment variables}).  The default is to
make working files writable, unless watches are on
(@pxref{Watches}).

@item -s @var{variable}=@var{value}
Set a user variable (@pxref{Variables}).

@cindex Trace
@item -t
Trace program execution; display messages showing the steps of
@sc{cvs} activity.  Particularly useful with @samp{-n} to explore the
potential impact of an unfamiliar command.

@item -v
Display version and copyright information for @sc{cvs}.

@cindex CVSREAD, overriding
@cindex Overriding CVSREAD
@item -w
Make new working files read-write.  Overrides the
setting of the @code{$CVSREAD} environment variable.
Files are created read-write by default, unless @code{$CVSREAD} is
set or @samp{-r} is given.

@item -z @var{gzip-level}
Set the compression level.  Only has an effect on the
@sc{cvs} client.

@end table

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Common options
@appendixsec Common command options
@cindex Common options
@cindex Right-hand options

This section describes the @samp{command_options} that
are available across several @sc{cvs} commands.  These
options are always given to the right of
@samp{cvs_command}. Not all
commands support all of these options; each option is
only supported for commands where it makes sense.
However, when a command has one of these options you
can almost always count on the same behavior of the
option as in other commands.  (Other command options,
which are listed with the individual commands, may have
different behavior from one @sc{cvs} command to the other).

@strong{Warning:} the @samp{history} command is an exception; it supports
many options that conflict even with these standard options.

@table @code
@cindex Dates
@cindex Time
@cindex Specifying dates
@item -D @var{date_spec}
Use the most recent revision no later than @var{date_spec}.
@var{date_spec} is a single argument, a date description
specifying a date in the past.

The specification is @dfn{sticky} when you use it to make a
private copy of a source file; that is, when you get a working
file using @samp{-D}, @sc{cvs} records the date you specified, so that
further updates in the same directory will use the same date
(for more information on sticky tags/dates, @pxref{Sticky tags}).

A wide variety of date formats are supported by the underlying
@sc{rcs} facilities, similar to those described in co(1), but not
exactly the same.  The @var{date_spec} is interpreted as being
in the local timezone, unless a specific timezone is specified.
Examples of valid date specifications include:

@example
                    1 month ago
                    2 hours ago
                    400000 seconds ago
                    last year
                    last Monday
                    yesterday
                    a fortnight ago
                    3/31/92 10:00:07 PST
                    January 23, 1987 10:05pm
                    22:00 GMT
@end example

@samp{-D} is available with the @code{checkout},
@code{diff}, @code{export}, @code{history},
@code{rdiff}, @code{rtag}, and @code{update} commands.
(The @code{history} command uses this option in a
slightly different way; @pxref{history options}).

Remember to quote the argument to the @samp{-D}
flag so that your shell doesn't interpret spaces as
argument separators.  A command using the @samp{-D}
flag can look like this:

@example
$ cvs diff -D "1 hour ago" cvs.texinfo
@end example

@cindex Forcing a tag match
@item -f
When you specify a particular date or tag to @sc{cvs} commands, they
normally ignore files that do not contain the tag (or did not
exist prior to the date) that you specified.  Use the @samp{-f} option
if you want files retrieved even when there is no match for the
tag or date.  (The most recent revision of the file
will be used). 

@need 800
@samp{-f} is available with these commands: @code{checkout},
@code{export}, @code{rdiff}, @code{rtag}, and @code{update}.

@strong{Warning:}  The @code{commit} command also has a
@samp{-f} option, but it has a different behavior for
that command.  @xref{commit options}.

@item -H
Help; describe the options available for this command.  This is
the only option supported for all @sc{cvs} commands.

@item -k @var{kflag}
Alter the default @sc{rcs} processing of keywords.
@xref{Keyword substitution}, for the meaning of
@var{kflag}.  Your @var{kflag} specification is
@dfn{sticky} when you use it to create a private copy
of a source file; that is, when you use this option
with the @code{checkout} or @code{update} commands,
@sc{cvs} associates your selected @var{kflag} with the
file, and continues to use it with future update
commands on the same file until you specify otherwise.

The @samp{-k} option is available with the @code{add},
@code{checkout}, @code{diff} and
@code{update} commands.

@item -l
Local; run only in current working directory, rather than
recursing through subdirectories.  

@strong{Warning:} this is not the same
as the overall @samp{cvs -l} option, which you can specify to the
left of a cvs command!

Available with the following commands: @code{checkout},
@code{commit}, @code{diff}, @code{export}, @code{log},
@code{remove}, @code{rdiff}, @code{rtag},
@code{status}, @code{tag}, and @code{update}.

@cindex Editor, avoiding invocation of
@cindex Avoiding editor invocation
@item -m @var{message}
Use @var{message} as log information, instead of
invoking an editor.

Available with the following commands: @code{add},
@code{commit} and @code{import}.

@item -n
Do not run any checkout/commit/tag program.  (A program can be
specified to run on each of these activities, in the modules
database (@pxref{modules}); this option bypasses it). 

@strong{Warning:} this is not the same as the overall @samp{cvs -n}
option, which you can specify to the left of a cvs command!

Available with the @code{checkout}, @code{commit}, @code{export},
and @code{rtag} commands.

@item -P
Prune (remove) directories that are empty after being updated, on
@code{checkout}, or @code{update}.  Normally, an empty directory
(one that is void of revision-controlled files) is left alone.
Specifying @samp{-P} will cause these directories to be silently
removed from your checked-out sources.  This does not remove the
directory from the repository, only from your checked out copy.
Note that this option is implied by the @samp{-r} or @samp{-D}
options of @code{checkout} and @code{export}.
@c -- implied--

@item -p
Pipe the files retrieved from the repository to standard output,
rather than writing them in the current directory.  Available
with the @code{checkout} and @code{update} commands.

@item -W
Specify file names that should be filtered.  You can
use this option repeatedly.  The spec can be a file
name pattern of the same type that you can specify in
the @file{.cvswrappers} file.
Avaliable with the following commands: @code{import},
and @code{update}.

@item -r @var{tag}
Use the revision specified by the @var{tag} argument instead of the
default @dfn{head} revision.  As well as arbitrary tags defined
with the @code{tag} or @code{rtag} command, two special tags are
always available: @samp{HEAD} refers to the most recent version
available in the repository, and @samp{BASE} refers to the
revision you last checked out into the current working directory.

The tag specification is sticky when you use this option
with @code{checkout} or @code{update} to make your own
copy of a file: @sc{cvs} remembers the tag and continues to use it on
future update commands, until you specify otherwise (for more information
on sticky tags/dates, @pxref{Sticky tags}).  The
tag can be either a symbolic or numeric tag.
@xref{Tags}.

Specifying the @samp{-q} global option along with the
@samp{-r} command option is often useful, to suppress
the warning messages when the @sc{rcs} history file
does not contain the specified tag.

@strong{Warning:} this is not the same as the overall `cvs -r' option,
which you can specify to the left of a cvs command!

@samp{-r} is available with the @code{checkout}, @code{commit},
@code{diff}, @code{history}, @code{export}, @code{rdiff},
@code{rtag}, and @code{update} commands.

@end table

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node add
@appendixsec add---Add a new file/directory to the repository
@cindex Add (subcommand)

@itemize @bullet
@item
Synopsis: add [-k kflag] [-m 'message'] files@dots{}
@item
Requires: repository, working directory.
@item
Changes: working directory.
@item
Synonym: new
@end itemize

Use the @code{add} command to create a new file or directory in the 
source repository.  The files or directories specified with @code{add}
must already exist in the current directory (which must have been
created with the @code{checkout} command).  To add a whole new directory
hierarchy to the source repository (for example, files received
from a third-party vendor), use the @code{import} command
instead.  @xref{import}.

If the argument to @code{add} refers to an immediate
sub-directory, the directory is created at the correct place in
the source repository, and the necessary @sc{cvs} administration
files are created in your working directory.  If the directory
already exists in the source repository, @code{add} still creates
the administration files in your version of the directory.
This allows you to use @code{add} to add a particular directory
to your private sources even if someone else created that
directory after your checkout of the sources.  You can do the
following:

@example
$ mkdir new_directory
$ cvs add new_directory
$ cvs update new_directory
@end example

An alternate approach using @code{update} might be:

@example
$ cvs update -d new_directory
@end example

(To add any available new directories to your working directory,
it's probably simpler to use @code{checkout} (@pxref{checkout})
or @samp{update -d} (@pxref{update})).

The added files are not placed in the source repository until you
use @code{commit} to make the change permanent.  Doing an
@code{add} on a file that was removed with the @code{remove}
command will resurrect the file, unless a @code{commit} command
intervened.
@xref{Removing files}, for an example.


Unlike most other commands @code{add} never recurses down
directories.  It cannot yet handle relative paths.  Instead of

@example
$ cvs add foo/bar.c
@end example

you have to do

@example
$ cd foo
$ cvs add bar.c
@end example

@menu
* add options::                 add options
* add examples::                add examples
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node add options
@appendixsubsec add options
@cindex Add options

There are only two options you can give to @samp{add}:

@table @code
@item -k @var{kflag}
This option specifies the default way that this file
will be checked out.  The @var{kflag} argument
(@pxref{Substitution modes}) is stored in the @sc{rcs}
file and can be changed with @code{admin -k}
(@pxref{admin options}).  See @ref{Binary files}, for
information on using this option for binary files.

@item -m @var{description}
Using this option, you can give a description for the file.  This
description appears in the history log (if it is enabled,
@pxref{history file}).  It will also be saved in the @sc{rcs} history
file inside the repository when the file is committed.  The
@code{log} command displays this description.

The description can be changed using @samp{admin -t}.
@xref{admin}.

If you omit the @samp{-m @var{description}} flag, an empty string will be
used.  You will not be prompted for a description.
@end table

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node add examples
@appendixsubsec add examples

To add the file @file{backend.c} to the repository, with a
description, the following can be used.

@example
$ cvs add -m "Optimizer and code generation passes." backend.c
$ cvs commit -m "Early version. Not yet compilable." backend.c
@end example

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node admin
@appendixsec admin---Administration front end for rcs
@cindex Admin (subcommand)

@itemize @bullet
@item
Requires: repository, working directory.
@item
Changes: repository.
@item
Synonym: rcs
@end itemize

This is the @sc{cvs} interface to assorted administrative @sc{rcs}
facilities, documented in rcs(1).  @code{admin} simply passes
all its options and arguments to the @code{rcs} command; it does
no filtering or other processing.  This command @emph{does} work
recursively, however, so extreme care should be used.

If there is a group whose name matches a compiled in
value which defaults to @code{cvsadmin}, only members
of that group can use @code{cvs admin}.  To disallow
@code{cvs admin} for all users, create a group with no
users in it.

@menu
* admin options::               admin options
* admin examples::              admin examples
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node admin options
@appendixsubsec admin options

Not all valid @code{rcs} options are useful together
with @sc{cvs}.  Some even makes it impossible to use
@sc{cvs} until you undo the effect!

This description of the available options is based on
the @samp{rcs(1)} man page, but modified to suit
readers that are more interrested in @sc{cvs} than
@sc{rcs}.

@table @code
@item -A@var{oldfile}
Might not work together with @sc{cvs}.  Append the
access list of @var{oldfile} to the access list of the
@sc{rcs} file.

@item -a@var{logins}
Might not work together with @sc{cvs}.  Append the
login names appearing in the comma-separated list
@var{logins} to the access list of the @sc{rcs} file.

@item -b[@var{rev}]
When used with bare @sc{rcs}, this
option sets the default branch to @var{rev}; in
@sc{cvs} sticky tags (@pxref{Sticky tags}) are a better
way to decide which branch you want to work on.  With
@sc{cvs}, this option can be used to control behavior
with respect to the vendor branch.
@c FIXME: document how you use it with the vendor
@c branch (or fix cvs so that there is a more graceful
@c way to handle the case).

@item -c@var{string}
Useful with @sc{cvs}.  Sets the comment leader to
@var{string}.  The comment leader is printed before
every log message line generated by the keyword
@code{$@asis{}Log$} (@pxref{Keyword substitution}).
This is useful for programming languages without
multi-line comments.  @sc{Rcs} initially guesses the
value of the comment leader from the file name
extension when the file is first committed.

@item -e[@var{logins}]
Might not work together with @sc{cvs}.  Erase the login
names appearing in the comma-separated list
@var{logins} from the access list of the RCS file.  If
@var{logins} is omitted, erase the entire access list.

@item -I
Run interactively, even if the standard input is not a
terminal.

@item -i
Useless with @sc{cvs}.  When using bare @sc{rcs}, this
is used to create and initialize a new @sc{rcs} file,
without depositing a revision.

@item -k@var{subst}
Useful with @sc{cvs}.  Set the default keyword
substitution to @var{subst}.  @xref{Keyword
substitution}.  Giving an explicit @samp{-k} option to
@code{cvs update}, @code{cvs export}, or @code{cvs
checkout} overrides this default.

@cindex Reserved checkouts
@cindex RCS-style locking
@item -l[@var{rev}]
Lock the revision with number @var{rev}.  If a branch
is given, lock the latest revision on that branch.  If
@var{rev} is omitted, lock the latest revision on the
default branch.

This can be used in conjunction with the
@file{rcslock.pl} script in the @file{contrib}
directory of the @sc{cvs} source distribution to
provide reserved checkouts (where only one user can be
editing a given file at a time).  See the comments in
that file for details (and see the @file{README} file
in that directory for disclaimers about the unsupported
nature of contrib).  According to comments in that
file, locking must set to strict (which is the default).

@item -L
Set locking to strict.  Strict locking means that the
owner of an RCS file is not exempt from locking for
checkin.  For use with @sc{cvs}, strict locking must be
set; see the discussion under the @samp{-l} option above.

@cindex Changing a log message
@cindex Replacing a log message
@cindex Correcting a log message
@cindex Fixing a log message
@cindex Log message, correcting
@item -m@var{rev}:@var{msg}
Replace the log message of revision @var{rev} with
@var{msg}.

@item -N@var{name}[:[@var{rev}]]
Act like @samp{-n}, except override any previous
assignment of @var{name}.

@item -n@var{name}[:[@var{rev}]]
Associate the symbolic name @var{name} with the branch
or revision @var{rev}.  It is normally better to use
@samp{cvs tag} or @samp{cvs rtag} instead.  Delete the
symbolic name if both @samp{:} and @var{rev} are
omitted; otherwise, print an error message if
@var{name} is already associated with another number.
If @var{rev} is symbolic, it is expanded before
association.  A @var{rev} consisting of a branch number
followed by a @samp{.} stands for the current latest
revision in the branch.  A @samp{:} with an empty
@var{rev} stands for the current latest revision on the
default branch, normally the trunk.  For example,
@samp{rcs -n@var{name}: RCS/*} associates @var{name} with the
current latest revision of all the named RCS files;
this contrasts with @samp{rcs -n@var{name}:$ RCS/*} which
associates @var{name} with the revision numbers
extracted from keyword strings in the corresponding
working files.

@cindex Deleting revisions
@cindex Outdating revisions
@cindex Saving space
@item -o@var{range}
Potentially useful, but dangerous, with @sc{cvs} (see below).
Deletes (@dfn{outdates}) the revisions given by
@var{range}.  A range consisting of a single revision
number means that revision.  A range consisting of a
branch number means the latest revision on that branch.
A range of the form @samp{@var{rev1}:@var{rev2}} means
revisions @var{rev1} to @var{rev2} on the same branch,
@samp{:@var{rev}} means from the beginning of the
branch containing @var{rev} up to and including
@var{rev}, and @samp{@var{rev}:} means from revision
@var{rev} to the end of the branch containing
@var{rev}.  None of the outdated revisions may have
branches or locks.

Due to the way @sc{cvs} handles branches @var{rev}
cannot be specified symbolically if it is a branch.
@xref{Magic branch numbers}, for an explanation.

Make sure that no-one has checked out a copy of the
revision you outdate.  Strange things will happen if he
starts to edit it and tries to check it back in.  For
this reason, this option is not a good way to take back
a bogus commit; commit a new revision undoing the bogus
change instead (@pxref{Merging two revisions}).

@item -q
Run quietly; do not print diagnostics.

@item -s@var{state}[:@var{rev}]
Useful with @sc{cvs}.  Set the state attribute of the
revision @var{rev} to @var{state}.  If @var{rev} is a
branch number, assume the latest revision on that
branch.  If @var{rev} is omitted, assume the latest
revision on the default branch.  Any identifier is
acceptable for @var{state}.  A useful set of states is
@samp{Exp} (for experimental), @samp{Stab} (for
stable), and @samp{Rel} (for released).  By default,
the state of a new revision is set to @samp{Exp} when
it is created.  The state is visible in the output from
@var{cvs log} (@pxref{log}), and in the
@samp{$@asis{}Log$} and @samp{$@asis{}State$} keywords
(@pxref{Keyword substitution}).  Note that @sc{cvs}
uses the @code{dead} state for its own purposes; to
take a file to or from the @code{dead} state use
commands like @code{cvs remove} and @code{cvs add}, not
@code{cvs admin -s}.

@item -t[@var{file}]
Useful with @sc{cvs}.  Write descriptive text from the
contents of the named @var{file} into the RCS file,
deleting the existing text.  The @var{file} pathname
may not begin with @samp{-}.  If @var{file} is omitted,
obtain the text from standard input, terminated by
end-of-file or by a line containing @samp{.} by itself.
Prompt for the text if interaction is possible; see
@samp{-I}.  The descriptive text can be seen in the
output from @samp{cvs log} (@pxref{log}).

@item -t-@var{string}
Similar to @samp{-t@var{file}}. Write descriptive text
from the @var{string} into the @sc{rcs} file, deleting
the existing text.

@item -U
Set locking to non-strict.  Non-strict locking means
that the owner of a file need not lock a revision for
checkin.  For use with @sc{cvs}, strict locking must be
set; see the discussion under the @samp{-l} option
above.

@item -u[@var{rev}]
See the option @samp{-l} above, for a discussion of
using this option with @sc{cvs}.  Unlock the revision
with number @var{rev}.  If a branch is given, unlock
the latest revision on that branch.  If @var{rev} is
omitted, remove the latest lock held by the caller.
Normally, only the locker of a revision may unlock it.
Somebody else unlocking a revision breaks the lock.
This causes a mail message to be sent to the original
locker.  The message contains a commentary solicited
from the breaker.  The commentary is terminated by
end-of-file or by a line containing @code{.} by itself.

@item -V@var{n}
Emulate @sc{rcs} version @var{n}. Use -V@var{n} to make
an @sc{rcs} file acceptable to @sc{rcs} version @var{n}
by discarding information that would confuse version
@var{n}.

@item -x@var{suffixes}
Useless with @sc{cvs}. Use @var{suffixes} to
characterize RCS files.
@end table


@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node admin examples
@appendixsubsec admin examples

@appendixsubsubsec Outdating is dangerous

First, an example of how @emph{not} to use the
@code{admin} command.  It is included to stress the
fact that this command can be quite dangerous unless
you know @emph{exactly} what you are doing.

The @samp{-o} option can be used to @dfn{outdate} old revisions
from the history file.  If you are short on disc this option
might help you.  But think twice before using it---there is no
way short of restoring the latest backup to undo this command!

The next line is an example of a command that you would
@emph{not} like to execute.

@example
$ cvs admin -o:R_1_02 .
@end example

The above command will delete all revisions up to, and
including, the revision that corresponds to the tag
R_1_02.  But beware!  If there are files that have not
changed between R_1_02 and R_1_03 the file will have
@emph{the same} numerical revision number assigned to
the tags R_1_02 and R_1_03.  So not only will it be
impossible to retrieve R_1_02; R_1_03 will also have to
be restored from the tapes!

@appendixsubsubsec Comment leaders
@cindex Comment leader
@cindex Log keyword, selecting comment leader
@cindex Nroff (selecting comment leader)

If you use the @code{$@asis{}Log$} keyword and you do
not agree with the guess for comment leader that
@sc{cvs} has done, you can enforce your will with
@code{cvs admin -c}.  This might be suitable for
@code{nroff} source:

@example
$ cvs admin -c'.\" ' *.man
$ rm *.man
$ cvs update
@end example

The two last steps are to make sure that you get the
versions with correct comment leaders in your working
files.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node checkout
@appendixsec checkout---Check out sources for editing
@cindex Checkout (subcommand)
@cindex Co (subcommand)

@itemize @bullet
@item
Synopsis: checkout [options] modules@dots{}
@item
Requires: repository.
@item
Changes: working directory.
@item
Synonyms: co, get
@end itemize

Make a working directory containing copies of the
source files specified by @var{modules}.  You must execute
@code{checkout} before using most of the other @sc{cvs}
commands, since most of them operate on your working
directory.

The @var{modules} part of the command are either
symbolic names for some
collection of source directories and files, or paths to
directories or files in the repository.  The symbolic
names are defined in the @samp{modules} file.
@xref{modules}.

Depending on the modules you specify, @code{checkout} may
recursively create directories and populate them with
the appropriate source files.  You can then edit these
source files at any time (regardless of whether other
software developers are editing their own copies of the
sources); update them to include new changes applied by
others to the source repository; or commit your work as
a permanent change to the source repository.

Note that @code{checkout} is used to create
directories.  The top-level directory created is always
added to the directory where @code{checkout} is
invoked, and usually has the same name as the specified
module.  In the case of a module alias, the created
sub-directory may have a different name, but you can be
sure that it will be a sub-directory, and that
@code{checkout} will show the relative path leading to
each file as it is extracted into your private work
area (unless you specify the @samp{-Q} global option).

The files created by @code{checkout} are created
read-write, unless the @samp{-r} option to @sc{cvs}
(@pxref{Global options}) is specified, the
@code{CVSREAD} environment variable is specified
(@pxref{Environment variables}), or a watch is in
effect for that file (@pxref{Watches}).

@c FIXME: misleading--checkout takes a module as
@c argument, and update does not--so -d behavior is not the only
@c difference.
Running @code{checkout} on a directory that was already
built by a prior @code{checkout} is also permitted, and
has the same effect as specifying the @samp{-d} option
to the @code{update} command, that is, any new
directories that have been created in the repository
will appear in your work area.  @xref{update}.

@menu
* checkout options::            checkout options
* checkout examples::           checkout examples
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node checkout options
@appendixsubsec checkout options

These standard options are supported by @code{checkout}
(@pxref{Common options}, for a complete description of
them):

@table @code
@item -D @var{date}
Use the most recent revision no later than @var{date}.
This option is sticky, and implies @samp{-P}.  See
@ref{Sticky tags}, for more information on sticky tags/dates.

@item -f
Only useful with the @samp{-D @var{date}} or @samp{-r
@var{tag}} flags.  If no matching revision is found,
retrieve the most recent revision (instead of ignoring
the file).

@item -k @var{kflag}
Process @sc{rcs} keywords according to @var{kflag}.  See
co(1).  This option is sticky; future updates of
this file in this working directory will use the same
@var{kflag}.  The @code{status} command can be viewed
to see the sticky options.  @xref{status}.

@item -l
Local; run only in current working directory.

@item -n
Do not run any checkout program (as specified
with the @samp{-o} option in the modules file;
@pxref{modules}).

@item -P
Prune empty directories.

@item -p
Pipe files to the standard output.

@item -r @var{tag}
Use revision @var{tag}.  This option is sticky, and implies @samp{-P}.
See @ref{Sticky tags}, for more information on sticky tags/dates.
@end table

In addition to those, you can use these special command
options with @code{checkout}:

@table @code
@item -A
Reset any sticky tags, dates, or @samp{-k} options.
See @ref{Sticky tags}, for more information on sticky tags/dates.

@item -c
Copy the module file, sorted, to the standard output,
instead of creating or modifying any files or
directories in your working directory.

@item -d @var{dir}
Create a directory called @var{dir} for the working
files, instead of using the module name.  Unless you
also use @samp{-N}, the paths created under @var{dir}
will be as short as possible.

@item -j @var{tag}
With two @samp{-j} options, merge changes from the
revision specified with the first @samp{-j} option to
the revision specified with the second @samp{j} option,
into the working directory.

With one @samp{-j} option, merge changes from the
ancestor revision to the revision specified with the
@samp{-j} option, into the working directory.  The
ancestor revision is the common ancestor of the
revision which the working directory is based on, and
the revision specified in the @samp{-j} option.

In addition, each -j option can contain an optional
date specification which, when used with branches, can
limit the chosen revision to one within a specific
date.  An optional date is specified by adding a colon
(:) to the tag:
@samp{-j@var{Symbolic_Tag}:@var{Date_Specifier}}.

@xref{Merging}.

@item -N
Only useful together with @samp{-d @var{dir}}.  With this
option, @sc{cvs} will not shorten module paths in your
working directory.  (Normally, @sc{cvs} shortens paths as
much as possible when you specify an explicit target
directory).

@item -s
Like @samp{-c}, but include the status of all modules,
and sort it by the status string.  @xref{modules}, for
info about the @samp{-s} option that is used inside the
modules file to set the module status.
@end table

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node checkout examples
@appendixsubsec checkout examples

Get a copy of the module @samp{tc}:

@example
$ cvs checkout tc
@end example

Get a copy of the module @samp{tc} as it looked one day
ago:

@example
$ cvs checkout -D yesterday tc
@end example

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node commit
@appendixsec commit---Check files into the repository
@cindex Commit (subcommand)

@itemize @bullet
@item
Version 1.3 Synopsis: commit [-lnR] [-m 'log_message' |
-f file] [-r revision] [files@dots{}]
@item
Version 1.3.1 Synopsis: commit [-lnRf] [-m 'log_message' |
-F file] [-r revision] [files@dots{}]
@c -- rename-f-F--
@item
Requires: working directory, repository.
@item
Changes: repository.
@item
Synonym: ci
@end itemize

@strong{Warning:} The @samp{-f @var{file}} option will
probably be renamed to @samp{-F @var{file}}, and @samp{-f}
will be given a new behavior in future releases of @sc{cvs}.
@c -- rename-f-F--

Use @code{commit} when you want to incorporate changes
from your working source files into the source
repository.

If you don't specify particular files to commit, all of
the files in your working current directory are
examined.  @code{commit} is careful to change in the
repository only those files that you have really
changed.  By default (or if you explicitly specify the
@samp{-R} option), files in subdirectories are also
examined and committed if they have changed; you can
use the @samp{-l} option to limit @code{commit} to the
current directory only.

@code{commit} verifies that the selected files are up
to date with the current revisions in the source
repository; it will notify you, and exit without
committing, if any of the specified files must be made
current first with @code{update} (@pxref{update}).
@code{commit} does not call the @code{update} command
for you, but rather leaves that for you to do when the
time is right.

When all is well, an editor is invoked to allow you to
enter a log message that will be written to one or more
logging programs (@pxref{modules}, and @pxref{loginfo})
and placed in the @sc{rcs} history file inside the
repository.  This log message can be retrieved with the
@code{log} command; @xref{log}.  You can specify the
log message on the command line with the @samp{-m
@var{message}} option, and thus avoid the editor invocation,
or use the @samp{-f @var{file}} option to specify
@c -- rename-f-F--
that the argument file contains the log message.

@menu
* commit options::              commit options
* commit examples::             commit examples
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node commit options
@appendixsubsec commit options

These standard options are supported by @code{commit}
(@pxref{Common options}, for a complete description of
them):

@table @code
@item -l
Local; run only in current working directory.

@item -n
Do not run any module program.

@item -R
Commit directories recursively.  This is on by default.

@item -r @var{revision}
Commit to @var{revision}.  @var{revision} must be
either a branch, or a revision on the main trunk that
is higher than any existing revision number.  You
cannot commit to a specific revision on a branch.
@end table

@code{commit} also supports these options:

@table @code
@item -F @var{file}
This option is present in @sc{cvs} releases 1.3-s3 and
later.  Read the log message from @var{file}, instead
of invoking an editor.

@item -f
@c -- rename-f-F--
This option is present in @sc{cvs} 1.3-s3 and later releases
of @sc{cvs}.  Note that this is not the standard behavior of
the @samp{-f} option as defined in @xref{Common options}.

Force @sc{cvs} to commit a new revision even if you haven't
made any changes to the file.  If the current revision
of @var{file} is 1.7, then the following two commands
are equivalent:

@example
$ cvs commit -f @var{file}
$ cvs commit -r 1.8 @var{file}
@end example

@item -f @var{file}
@c -- rename-f-F--
This option is present in @sc{cvs} releases 1.3, 1.3-s1 and
1.3-s2.  Note that this is not the standard behavior of
the @samp{-f} option as defined in @xref{Common options}.

Read the log message from @var{file}, instead
of invoking an editor.

@item -m @var{message}
Use @var{message} as the log message, instead of
invoking an editor.
@end table

@need 2000
@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node commit examples
@appendixsubsec commit examples

@appendixsubsubsec New major release number

When you make a major release of your product, you
might want the revision numbers to track your major
release number.  You should normally not care about
the revision numbers, but this is a thing that many
people want to do, and it can be done without doing any
harm.

To bring all your files up to the @sc{rcs} revision 3.0
(including those that haven't changed), you might do:

@example
$ cvs commit -r 3.0
@end example

Note that it is generally a bad idea to try to make the
@sc{rcs} revision number equal to the current release number
of your product.  You should think of the revision
number as an internal number that the @sc{cvs} package
maintains, and that you generally never need to care
much about.  Using the @code{tag} and @code{rtag}
commands you can give symbolic names to the releases
instead.  @xref{tag} and @xref{rtag}.

Note that the number you specify with @samp{-r} must be
larger than any existing revision number.  That is, if
revision 3.0 exists, you cannot @samp{cvs commit
-r 1.3}.

@appendixsubsubsec Committing to a branch

You can commit to a branch revision (one that has an
even number of dots) with the @samp{-r} option.  To
create a branch revision, use the @samp{-b} option
of the @code{rtag} or @code{tag} commands (@pxref{tag}
or @pxref{rtag}).  Then, either @code{checkout} or
@code{update} can be used to base your sources on the
newly created branch.  From that point on, all
@code{commit} changes made within these working sources
will be automatically added to a branch revision,
thereby not disturbing main-line development in any
way.  For example, if you had to create a patch to the
1.2 version of the product, even though the 2.0 version
is already under development, you might do:

@example
$ cvs rtag -b -r FCS1_2 FCS1_2_Patch product_module
$ cvs checkout -r FCS1_2_Patch product_module
$ cd product_module
[[ hack away ]]
$ cvs commit
@end example

@noindent
This works automatically since the @samp{-r} option is
sticky.

@appendixsubsubsec Creating the branch after editing

Say you have been working on some extremely
experimental software, based on whatever revision you
happened to checkout last week.  If others in your
group would like to work on this software with you, but
without disturbing main-line development, you could
commit your change to a new branch.  Others can then
checkout your experimental stuff and utilize the full
benefit of @sc{cvs} conflict resolution.  The scenario might
look like:

@c FIXME: Should we be recommending tagging the branchpoint?
@example
[[ hacked sources are present ]]
$ cvs tag -b EXPR1
$ cvs update -r EXPR1
$ cvs commit
@end example

The @code{update} command will make the @samp{-r
EXPR1} option sticky on all files.  Note that your
changes to the files will never be removed by the
@code{update} command.  The @code{commit} will
automatically commit to the correct branch, because the
@samp{-r} is sticky.  You could also do like this:

@c FIXME: Should we be recommending tagging the branchpoint?
@example
[[ hacked sources are present ]]
$ cvs tag -b EXPR1
$ cvs commit -r EXPR1
@end example

@noindent
but then, only those files that were changed by you
will have the @samp{-r EXPR1} sticky flag.  If you hack
away, and commit without specifying the @samp{-r EXPR1}
flag, some files may accidentally end up on the main
trunk.

To work with you on the experimental change, others
would simply do

@example
$ cvs checkout -r EXPR1 whatever_module
@end example

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node diff
@appendixsec diff---Run diffs between revisions
@cindex Diff (subcommand)

@itemize @bullet
@item
Synopsis: diff [-l] [rcsdiff_options] [[-r rev1 | -D date1] [-r rev2 |  -D date2]] [files@dots{}]
@item
Requires: working directory, repository.
@item
Changes: nothing.
@end itemize

The @code{diff} command is used to compare different
revisions of files.  The default action is to compare
your working files with the revisions they were based
on, and report any differences that are found.

If any file names are given, only those files are
compared.  If any directories are given, all files
under them will be compared.

The exit status will be 0 if no differences were found,
1 if some differences were found, and 2 if any error
occurred.

@menu
* diff options::                diff options
* diff examples::               diff examples
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node diff options
@appendixsubsec diff options

These standard options are supported by @code{diff}
(@pxref{Common options}, for a complete description of
them):

@table @code
@item -D @var{date}
Use the most recent revision no later than @var{date}.
See @samp{-r} for how this affects the comparison.

@sc{cvs} can be configured to pass the @samp{-D} option
through to @code{rcsdiff} (which in turn passes it on
to @code{diff}.  @sc{Gnu} diff uses @samp{-D} as a way to
put @code{cpp}-style @samp{#define} statements around the output
differences.  There is no way short of testing to
figure out how @sc{cvs} was configured.  In the default
configuration @sc{cvs} will use the @samp{-D @var{date}} option.

@item -k @var{kflag}
Process @sc{rcs} keywords according to @var{kflag}.  See
co(1).

@item -l
Local; run only in current working directory.

@item -R
Examine directories recursively.  This option is on by
default.

@item -r @var{tag}
Compare with revision @var{tag}.  Zero, one or two
@samp{-r} options can be present.  With no @samp{-r}
option, the working file will be compared with the
revision it was based on.  With one @samp{-r}, that
revision will be compared to your current working file.
With two @samp{-r} options those two revisions will be
compared (and your working file will not affect the
outcome in any way).

One or both @samp{-r} options can be replaced by a
@samp{-D @var{date}} option, described above.
@end table

Any other options that are found are passed through to
@code{rcsdiff}, which in turn passes them to
@code{diff}.  The exact meaning of the options depends
on which @code{diff} you are using.  The long options
introduced in @sc{gnu} diff 2.0 are not yet supported in
@sc{cvs}.  See the documentation for your @code{diff} to see
which options are supported.

@c -- Document some common useful diff options, such as
@c -u and -c.
@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node diff examples
@appendixsubsec diff examples

The following line produces a Unidiff (@samp{-u} flag)
between revision 1.14 and 1.19 of
@file{backend.c}.  Due to the @samp{-kk} flag no
keywords are substituted, so differences that only depend
on keyword substitution are ignored.

@example
$ cvs diff -kk -u -r 1.14 -r 1.19 backend.c
@end example

Suppose the experimental branch EXPR1 was based on a
set of files tagged RELEASE_1_0.  To see what has
happened on that branch, the following can be used:

@example
$ cvs diff -r RELEASE_1_0 -r EXPR1
@end example

A command like this can be used to produce a context
diff between two releases:

@example
$ cvs diff -c -r RELEASE_1_0 -r RELEASE_1_1 > diffs
@end example

If you are maintaining ChangeLogs, a command like the following
just before you commit your changes may help you write
the ChangeLog entry.  All local modifications that have
not yet been committed will be printed.

@example
$ cvs diff -u | less
@end example

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node export
@appendixsec export---Export sources from CVS, similar to checkout
@cindex Export (subcommand)

@itemize @bullet
@item
Synopsis: export [-flNn] [-r rev|-D date] [-k subst] [-d dir] module@dots{}
@item
Requires: repository.
@item
Changes: current directory.
@end itemize

This command is a variant of @code{checkout}; use it
when you want a copy of the source for module without
the @sc{cvs} administrative directories.  For example, you
might use @code{export} to prepare source for shipment
off-site.  This command requires that you specify a
date or tag (with @samp{-D} or @samp{-r}), so that you
can count on reproducing the source you ship to others.

One often would like to use @samp{-kv} with @code{cvs
export}.  This causes any @sc{rcs} keywords to be
expanded such that an import done at some other site
will not lose the keyword revision information.  But be
aware that doesn't handle an export containing binary
files correctly.  Also be aware that after having used
@samp{-kv}, one can no longer use the @code{ident}
command (which is part of the @sc{rcs} suite---see
ident(1)) which looks for @sc{rcs} keyword strings.  If
you want to be able to use @code{ident} you must not
use @samp{-kv}.

@menu
* export options::              export options
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node export options
@appendixsubsec export options

These standard options are supported by @code{export}
(@pxref{Common options}, for a complete description of
them):

@table @code
@item -D @var{date}
Use the most recent revision no later than @var{date}.

@item -f
If no matching revision is found, retrieve the most
recent revision (instead of ignoring the file).

@item -l
Local; run only in current working directory.

@item -n
Do not run any checkout program.

@item -R
Export directories recursively.  This is on by default.

@item -r @var{tag}
Use revision @var{tag}.
@end table

In addition, these options (that are common to
@code{checkout} and @code{export}) are also supported:

@table @code
@item -d @var{dir}
Create a directory called @var{dir} for the working
files, instead of using the module name.  Unless you
also use @samp{-N}, the paths created under @var{dir}
will be as short as possible.

@item -k @var{subst}
Set keyword expansion mode (@pxref{Substitution modes}).

@item -N
Only useful together with @samp{-d @var{dir}}.  With this
option, @sc{cvs} will not shorten module paths in your
working directory.  (Normally, @sc{cvs} shortens paths as
much as possible when you specify an explicit target
directory.)
@end table

@ignore
@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@c @node export examples
@appendixsubsec export examples

Contributed examples are gratefully accepted.
@c -- Examples here!!
@end ignore

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node history
@appendixsec history---Show status of files and users
@cindex History (subcommand)

@itemize @bullet
@item
Synopsis:     history [-report] [-flags] [-options args] [files@dots{}]
@item
Requires: the file @file{$CVSROOT/CVSROOT/history}
@item
Changes: nothing.
@end itemize

@sc{cvs} can keep a history file that tracks each use of the
@code{checkout}, @code{commit}, @code{rtag},
@code{update}, and @code{release} commands.  You can
use @code{history} to display this information in
various formats.

Logging must be enabled by creating the file
@file{$CVSROOT/CVSROOT/history}.

@strong{Warning:} @code{history} uses @samp{-f}, @samp{-l},
@samp{-n}, and @samp{-p} in ways that conflict with the
normal use inside @sc{cvs} (@pxref{Common options}).

@menu
* history options::             history options
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node history options
@appendixsubsec history options

Several options (shown above as @samp{-report})  control  what
kind of report is generated:

@table @code
@item -c
Report on each time commit was used (i.e., each time
the repository was modified).

@item -e 
Everything (all record types); equivalent to specifying
@samp{-xMACFROGWUT}.

@item -m @var{module}
Report on a particular module.  (You can meaningfully
use @samp{-m} more than once on the command line.)

@item -o
Report on checked-out modules.

@item -T
Report on all tags.

@item -x @var{type}
Extract a particular set of record types @var{type} from the @sc{cvs}
history.  The types are indicated by single letters,
which you may specify in combination.  

Certain commands have a single record type: 

@table @code
@item F
release
@item O
checkout
@item T
rtag
@end table

@noindent
One of four record types may result from an update:

@table @code
@item C
A merge was necessary but collisions were
detected (requiring manual merging).  
@item G
A merge was necessary and it succeeded.
@item U
A working file was copied from the repository.
@item W
The working copy of a file was deleted during
update (because it was gone from the repository).
@end table

@noindent
One of three record types results from commit:

@table @code
@item A
A file was added for the first time.
@item M
A file was modified.
@item R
A file was removed.
@end table
@end table

The options shown as @samp{-flags} constrain or expand
the report without requiring option arguments:

@table @code
@item -a
Show data for all users (the default is to show data
only for the user executing @code{history}).

@item -l
Show last modification only.

@item -w
Show only the records for modifications done from the
same working directory where @code{history} is
executing.
@end table

The options shown as @samp{-options @var{args}} constrain the report
based on an argument:

@table @code
@item -b @var{str}
Show data back to a record containing  the  string
@var{str}  in  either the module name, the file name, or
the repository path.

@item -D @var{date}
Show data since @var{date}.  This is slightly different
from the normal use of @samp{-D @var{date}}, which
selects the newest revision older than @var{date}.

@item -p @var{repository}
Show data for a particular source repository  (you
can specify several @samp{-p} options on the same command
line).

@item -r @var{rev}
Show records referring to revisions since the revision
or tag named @var{rev} appears in individual @sc{rcs}
files.  Each @sc{rcs} file is searched for the revision or
tag.

@item -t @var{tag}
Show records since tag @var{tag} was last added to the the
history file.  This differs from the @samp{-r} flag
above in that it reads only the history file, not the
@sc{rcs} files, and is much faster.

@item -u @var{name}
Show records for user @var{name}.
@end table

@ignore
@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@c @node history examples
@appendixsubsec history examples

Contributed examples will gratefully be accepted.
@c -- Examples here!
@end ignore

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node import
@appendixsec import---Import sources into CVS, using vendor branches
@cindex Import (subcommand)

@itemize @bullet
@item
Synopsis: import [-options] repository vendortag releasetag@dots{}
@item
Requires: Repository, source distribution directory.
@item
Changes: repository.
@end itemize

Use @code{import} to incorporate an entire source
distribution from an outside source (e.g., a source
vendor) into your source repository directory.  You can
use this command both for initial creation of a
repository, and for wholesale updates to the module
from the outside source.  @xref{Tracking sources}, for
a discussion on this subject.

The @var{repository} argument gives a directory name
(or a path to a directory) under the @sc{cvs} root directory
for repositories; if the directory did not exist,
import creates it.

When you use import for updates to source that has been
modified in your source repository (since a prior
import), it will notify you of any files that conflict
in the two branches of development; use @samp{checkout
-j} to reconcile the differences, as import instructs
you to do.

If @sc{cvs} decides a file should be ignored
(@pxref{cvsignore}), it does not import it and prints
@samp{I } followed by the filename

If the file @file{$CVSROOT/CVSROOT/cvswrappers} exists,
any file whose names match the specifications in that
file will be treated as packages and the appropriate
filtering will be performed on the file/directory
before being imported, @xref{Wrappers}.

The outside source is saved in a first-level @sc{rcs}
branch, by default 1.1.1.  Updates are leaves of this
branch; for example, files from the first imported
collection of source will be revision 1.1.1.1, then
files from the first imported update will be revision
1.1.1.2, and so on.

At least three arguments are required.
@var{repository} is needed to identify the collection
of source.  @var{vendortag} is a tag for the entire
branch (e.g., for 1.1.1).  You must also specify at
least one @var{releasetag} to identify the files at
the leaves created each time you execute @code{import}.

@menu
* import options::              import options
* import examples::             import examples
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node import options
@appendixsubsec import options

This standard option is supported by @code{import}
(@pxref{Common options}, for a complete description):

@table @code
@item -m @var{message}
Use @var{message} as log information, instead of
invoking an editor.
@end table

There are three additional special options.

@table @code
@item -b @var{branch}
Specify a first-level branch other than 1.1.1.  Unless
the @samp{-b @var{branch}} flag is given, revisions will
@emph{always} be made to the branch 1.1.1---even if a
@var{vendortag} that matches another branch is given!
What happens in that case, is that the tag will be
reset to 1.1.1.  Warning: This behavior might change
in the future.

@item -k @var{subst}
Indicate the RCS keyword expansion mode desired.  This
setting will apply to all files created during the
import, but not to any files that previously existed in
the repository.  See @ref{Substitution modes} for a
list of valid @samp{-k} settings.

@item -I @var{name}
Specify file names that should be ignored during
import.  You can use this option repeatedly.  To avoid
ignoring any files at all (even those ignored by
default), specify `-I !'.

@var{name} can be a file name pattern of the same type
that you can specify in the @file{.cvsignore} file.
@xref{cvsignore}.
@c -- Is this really true?

@item -W @var{spec}
Specify file names that should be filtered during
import.  You can use this option repeatedly.

@var{spec} can be a file name pattern of the same type
that you can specify in the @file{.cvswrappers}
file. @xref{Wrappers}.
@end table

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node import examples
@appendixsubsec import examples

@xref{Tracking sources}, and @xref{From files}.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node log
@appendixsec log---Print out 'rlog' information for files
@cindex Log (subcommand)

@itemize @bullet
@item
Synopsis: log [-l] rlog-options [files@dots{}]
@item
Requires: repository, working directory.
@item
Changes: nothing.
@item
Synonym: rlog
@end itemize

Display log information for files.  @code{log} calls
the @sc{rcs} utility @code{rlog}, which prints all available
information about the @sc{rcs} history file.  This includes
the location of the @sc{rcs} file, the @dfn{head} revision
(the latest revision on the trunk), all symbolic names (tags)
and some other things.  For each revision, the revision
number, the author, the number of lines added/deleted and
the log message are printed.  All times are displayed in
Coordinated Universal Time (UTC).  (Other parts of @sc{cvs}
print times in the local timezone).
@c -- timezone--

@menu
* log options::                 log options
* log examples::                log examples
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node log options
@appendixsubsec log options

Only one option is interpreted by @sc{cvs} and not passed on to @code{rlog}:

@table @code
@item -l
Local; run only in current working directory.  (Default
is to run recursively).
@end table

By default, @code{rlog} prints all information that is
available.  All other options (including those that
normally behave differently) are passed through to
@code{rlog} and restrict the output.  See rlog(1) for a
complete description of options.  This incomplete list
(which is a slightly edited extract from rlog(1)) lists
all options that are useful in conjunction with @sc{cvs}.

@strong{Please note:}  There can be no space between the option
and its argument, since @code{rlog} parses its options
in a different way than @sc{cvs}.

@table @code
@item -b
Print information about the revisions on the default
branch, normally the highest branch on the trunk.

@item -d@var{dates}
Print information about revisions with a checkin
date/time in the range given by the
semicolon-separated list of dates.  The following table
explains the available range formats:

@table @code
@item @var{d1}<@var{d2}
@itemx @var{d2}>@var{d1}
Select the revisions that were deposited between
@var{d1} and @var{d2} inclusive.

@item <@var{d}
@itemx @var{d}>
Select all revisions dated @var{d} or earlier.

@item @var{d}<
@itemx >@var{d}
Select all revisions dated @var{d} or later.

@item @var{d}
Select the single, latest revision dated @var{d} or
earlier.
@end table

The date/time strings @var{d}, @var{d1}, and @var{d2}
are in the free format explained in co(1).  Quoting is
normally necessary, especially for < and >.  Note that
the separator is a semicolon (;).

@item -h
Print only the @sc{rcs} pathname, working pathname, head,
default branch, access list, locks, symbolic names, and
suffix.

@item -N
Do not print the list of tags for this file.  This
option can be very useful when your site uses a lot of
tags, so rather than "more"'ing over 3 pages of tag
information, the log information is presented without
tags at all.  

@item -R
Print only the name of the @sc{rcs} history file.

@item -r@var{revisions}
Print information about revisions given in the
comma-separated list @var{revisions} of revisions and
ranges.  The following table explains the available
range formats:

@table @code
@item @var{rev1}:@var{rev2}
Revisions @var{rev1} to @var{rev2} (which must be on
the same branch).

@item :@var{rev}
Revisions from the beginning of the branch up to
and including @var{rev}.

@item @var{rev}: 
Revisions starting with @var{rev} to the end of the
branch containing @var{rev}.

@item @var{branch}
An argument that is a branch means all revisions on
that branch.  You can unfortunately not specify a
symbolic branch here.  You must specify the numeric
branch number.  @xref{Magic branch numbers}, for an
explanation.

@item @var{branch1}:@var{branch2}
A range of branches means all revisions
on the branches in that range.

@item @var{branch}.
The latest revision in @var{branch}.
@end table

A bare @samp{-r} with no revisions means the latest
revision on the default branch, normally the trunk.

@item -s@var{states}
Print information about revisions whose state
attributes match one of the states given in the
comma-separated list @var{states}.

@item -t
Print the same as @samp{-h}, plus the descriptive text.

@item -w@var{logins}
Print information about revisions checked in by users
with login names appearing in the comma-separated list
@var{logins}.  If @var{logins} is omitted, the user's
login is assumed.
@end table

@code{rlog} prints the intersection of the revisions
selected with the options @samp{-d}, @samp{-l},
@samp{-s}, and @samp{-w}, intersected with the union of
the revisions selected by @samp{-b} and @samp{-r}.

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node log examples
@appendixsubsec log examples

Contributed examples are gratefully accepted.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node rdiff
@appendixsec rdiff---'patch' format diffs between releases
@cindex Rdiff (subcommand)

@itemize @bullet
@item
rdiff [-flags] [-V vn] [-r t|-D d [-r t2|-D d2]] modules@dots{}
@item
Requires: repository.
@item
Changes: nothing.
@item
Synonym: patch
@end itemize

Builds a Larry Wall format patch(1) file between two
releases, that can be fed directly into the patch
program to bring an old release up-to-date with the new
release.  (This is one of the few @sc{cvs} commands that
operates directly from the repository, and doesn't
require a prior checkout.) The diff output is sent to
the standard output device.

You can specify (using the standard @samp{-r} and
@samp{-D} options) any combination of one or two
revisions or dates.  If only one revision or date is
specified, the patch file reflects differences between
that revision or date and the current head revisions in
the @sc{rcs} file.

Note that if the software release affected is contained
in more than one directory, then it may be necessary to
specify the @samp{-p} option to the patch command when
patching the old sources, so that patch is able to find
the files that are located in other directories.

@menu
* rdiff options::               rdiff options
* rdiff examples::              rdiff examples
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node rdiff options
@appendixsubsec rdiff options

These standard options are supported by @code{rdiff}
(@pxref{Common options}, for a complete description of
them):

@table @code
@item -D @var{date}
Use the most recent revision no later than @var{date}.

@item -f
If no matching revision is found, retrieve the most
recent revision (instead of ignoring the file).

@item -l
Local; don't descend subdirectories.

@item -r @var{tag}
Use revision @var{tag}.
@end table

In addition to the above, these options are available:

@table @code
@item -c
Use the context diff format.  This is the default format.

@item -s
Create a summary change report instead of a patch.  The
summary includes information about files that were
changed or added between the releases.  It is sent to
the standard output device.  This is useful for finding
out, for example, which files have changed between two
dates or revisions.

@item -t
A diff of the top two revisions is sent to the standard
output device.  This is most useful for seeing what the
last change to a file was.

@item -u
Use the unidiff format for the context diffs.
This option is not available if your diff does not
support the unidiff format.  Remember that old versions
of the @code{patch} program can't handle the unidiff
format, so if you plan to post this patch to the net
you should probably not use @samp{-u}.

@item -V @var{vn}
Expand @sc{rcs} keywords according to the rules current in
@sc{rcs} version @var{vn} (the expansion format changed with
@sc{rcs} version 5).
@end table

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node rdiff examples
@appendixsubsec rdiff examples

Suppose you receive mail from @t{foo@@bar.com} asking for an
update from release 1.2 to 1.4 of the tc compiler.  You
have no such patches on hand, but with @sc{cvs} that can
easily be fixed with a command such as this:

@example
$ cvs rdiff -c -r FOO1_2 -r FOO1_4 tc | \
$$ Mail -s 'The patches you asked for' foo@@bar.com
@end example

Suppose you have made release 1.3, and forked a branch
called @samp{R_1_3fix} for bugfixes.  @samp{R_1_3_1}
corresponds to release 1.3.1, which was made some time
ago.  Now, you want to see how much development has been
done on the branch.  This command can be used:

@example
$ cvs patch -s -r R_1_3_1 -r R_1_3fix module-name
cvs rdiff: Diffing module-name
File ChangeLog,v changed from revision 1.52.2.5 to 1.52.2.6
File foo.c,v changed from revision 1.52.2.3 to 1.52.2.4
File bar.h,v changed from revision 1.29.2.1 to 1.2
@end example

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node release
@appendixsec release---Indicate that a Module is no longer in use
@cindex Release (subcommand)

@itemize @bullet
@item
release [-d] directories@dots{}
@item
Requires: Working directory.
@item
Changes: Working directory, history log.
@end itemize

This command is meant to safely cancel the effect of
@samp{cvs checkout}.  Since @sc{cvs} doesn't lock files, it
isn't strictly necessary to use this command.  You can
always simply delete your working directory, if you
like; but you risk losing changes you may have
forgotten, and you leave no trace in the @sc{cvs} history
file (@pxref{history file}) that you've abandoned your
checkout.

Use @samp{cvs release} to avoid these problems.  This
command checks that no uncommitted changes are
present; that you are executing it from immediately
above a @sc{cvs} working directory; and that the repository
recorded for your files is the same as the repository
defined in the module database.

If all these conditions are true, @samp{cvs release}
leaves a record of its execution (attesting to your
intentionally abandoning your checkout) in the @sc{cvs}
history log.

@menu
* release options::             release options
* release output::              release options
* release examples::            release examples
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node release options
@appendixsubsec release options

The @code{release} command supports one command option:

@table @code
@item -d
Delete your working copy of the file if the release
succeeds.  If this flag is not given your files will
remain in your working directory.

@strong{Warning:}  The @code{release} command uses
@samp{rm -r @file{module}} to delete your file.  This
has the very serious side-effect that any directory
that you have created inside your checked-out sources,
and not added to the repository (using the @code{add}
command; @pxref{add}) will be silently deleted---even
if it is non-empty!
@end table

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node release output
@appendixsubsec release output

Before @code{release} releases your sources it will
print a one-line message for any file that is not
up-to-date.  

@strong{Warning:}  Any new directories that you have
created, but not added to the @sc{cvs} directory hierarchy
with the @code{add} command (@pxref{add}) will be
silently ignored (and deleted, if @samp{-d} is
specified), even if they contain files.

@table @code
@item U @var{file}
There exists a newer revision of this file in the
repository, and you have not modified your local copy
of the file.

@item A @var{file}
The file has been added to your private copy of the
sources, but has not yet been committed to the
repository.  If you delete your copy of the sources
this file will be lost.

@item R @var{file}
The file has been removed from your private copy of the
sources, but has not yet been removed from the
repository, since you have not yet committed the
removal.  @xref{commit}.

@item M @var{file}
The file is modified in your working directory.  There
might also be a newer revision inside the repository.

@item ? @var{file}
@var{file} is in your working directory, but does not
correspond to anything in the source repository, and is
not in the list of files for @sc{cvs} to ignore (see the
description of the @samp{-I} option, and
@pxref{cvsignore}).  If you remove your working
sources, this file will be lost.

Note that no warning message like this is printed for
spurious directories that @sc{cvs} encounters.  The
directory, and all its contents, are silently ignored.

@c FIXME -- CVS should be fixed to print "? foo" for
@c such spurious directories
@end table

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node release examples
@appendixsubsec release examples

Release the module, and delete your local working copy
of the files.

@example
$ cd ..         # @r{You must stand immediately above the}
                # @r{sources when you issue @samp{cvs release}.}
$ cvs release -d tc
You have [0] altered files in this repository.
Are you sure you want to release (and delete) module `tc': y
$
@end example

@node rtag
@appendixsec rtag---Add a tag to the RCS file
@cindex Rtag (subcommand)

@itemize @bullet
@item
rtag [-falnR] [-b] [-d] [-r tag | -Ddate] symbolic_tag modules@dots{}
@item
Requires: repository.
@item
Changes: repository.
@item
Synonym: rfreeze
@end itemize

You can use this command to assign symbolic tags to
particular, explicitly specified source revisions in
the repository.  @code{rtag} works directly on the
repository contents (and requires no prior checkout).
Use @code{tag} instead (@pxref{tag}), to base the
selection of revisions on the contents of your
working directory.

If you attempt to use a tag name that already exists,
@sc{cvs} will complain and not overwrite that tag.  Use
the @samp{-F} option to force the new tag value.

@menu
* rtag options::                rtag options
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node rtag options
@appendixsubsec rtag options

These standard options are supported by @code{rtag}
(@pxref{Common options}, for a complete description of
them):

@table @code
@item -D @var{date}
Tag the most recent revision no later than @var{date}.

@item -f
Only useful with the @samp{-D @var{date}} or @samp{-r @var{tag}}
flags.  If no matching revision is found, use the most
recent revision (instead of ignoring the file).

@item -F 
Overwrite an existing tag of the same name on a
different revision.  This option is new in @sc{cvs}
1.4.  The old behavior is matched by @samp{cvs tag -F}.

@item -l
Local; run only in current working directory.

@item -n
Do not run any tag program that was specified with the
@samp{-t} flag inside the @file{modules} file.
(@pxref{modules}).

@item -R
Commit directories recursively.  This is on by default.

@item -r @var{tag}
Only tag those files that contain @var{tag}.  This can
be used to rename a tag: tag only the files identified
by the old tag, then delete the old tag, leaving the
new tag on exactly the same files as the old tag.
@end table

In addition to the above common options, these options
are available:

@table @code
@item -a
Use the @samp{-a} option to have @code{rtag} look in the
@file{Attic} (@pxref{Removing files}) for removed files
that contain the specified tag.  The tag is removed from
these files, which makes it convenient to re-use a
symbolic tag as development continues (and files get
removed from the up-coming distribution).

@item -b
Make the tag a branch tag.  @xref{Branches}.

@item -d
Delete the tag instead of creating it.

In general, tags (often the symbolic names of software
distributions) should not be removed, but the @samp{-d}
option is available as a means to remove completely
obsolete symbolic names if necessary (as might be the
case for an Alpha release, or if you mistagged a
module).
@end table

@ignore
@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@c @node rtag examples
@appendixsubsec rtag examples

@c -- Examples here!
@end ignore

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node status
@appendixsec status---Status info on the revisions
@cindex Status (subcommand)

@itemize @bullet
@item
status [-lR] [-v] [files@dots{}]
@item
Requires: working directory, repository.
@item
Changes: nothing.
@end itemize

Display a brief report on the current status of files
with respect to the source repository, including any
sticky tags, dates, or @samp{-k} options.

You can also use this command to determine the
potential impact of a @samp{cvs update} on your working
source directory---but remember that things might
change in the repository before you run @code{update}.

@menu
* status options::              status options
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node status options
@appendixsubsec status options

These standard options are supported by @code{status}
(@pxref{Common options}, for a complete description of
them):

@table @code
@item -l
Local; run only in current working directory.

@item -R
Commit directories recursively.  This is on by default.
@end table

There is one additional option:

@table @code
@item -v
Verbose.  In addition to the information normally
displayed, print all symbolic tags, together with the
numerical value of the revision or branch they refer
to.
@end table

@ignore
@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@c @node status examples
@appendixsubsec status examples

@c -- FIXME
@end ignore

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node tag
@appendixsec tag---Add a symbolic tag to checked out version of RCS file
@c --                    //////// - unnecessary. Also
@c --                               in a lot of other
@c --                               places.
@cindex Tag (subcommand)

@itemize @bullet
@item
tag [-lR] [-b] [-d] symbolic_tag [files@dots{}]
@item
Requires: working directory, repository.
@item
Changes: repository.
@item
Synonym: freeze
@end itemize

Use this command to assign symbolic tags to the nearest
repository versions to your working sources.  The tags
are applied immediately to the repository, as with
@code{rtag}, but the versions are supplied implicitly by the
@sc{cvs} records of your working files' history rather than
applied explicitly.

One use for tags is to record a snapshot of the
current sources when the software freeze date of a
project arrives.  As bugs are fixed after the freeze
date, only those changed sources that are to be part of
the release need be re-tagged.

The symbolic tags are meant to permanently record which
revisions of which files were used in creating a
software distribution.  The @code{checkout} and
@code{update} commands allow you to extract an exact
copy of a tagged release at any time in the future,
regardless of whether files have been changed, added,
or removed since the release was tagged.

This command can also be used to delete a symbolic tag,
or to create a branch.  See the options section below.

If you attempt to use a tag name that already exists,
@sc{cvs} will complain and not overwrite that tag.  Use
the @samp{-F} option to force the new tag value.


@menu
* tag options::                 tag options
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node tag options
@appendixsubsec tag options

These standard options are supported by @code{tag}
(@pxref{Common options}, for a complete description of
them):

@table @code
@item -F 
Overwrite an existing tag of the same name on a
different revision.  This option is new in @sc{cvs}
1.4.  The old behavior is matched by @samp{cvs tag -F}.

@item -l
Local; run only in current working directory.

@item -R
Commit directories recursively.  This is on by default.
@end table

Two special options are available:

@table @code
@item -b
The -b option makes the tag a branch tag
(@pxref{Branches}), allowing concurrent, isolated
development.  This is most useful for creating a patch
to a previously released software distribution.

@item -d
Delete a tag.

If you use @samp{cvs tag -d symbolic_tag}, the symbolic
tag you specify is deleted instead of being added.
Warning: Be very certain of your ground before you
delete a tag; doing this permanently discards some
historical information, which may later turn out to
be valuable.
@end table

@ignore
@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@c @node tag examples
@appendixsubsec tag examples

@c -- FIXME
@end ignore

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node update
@appendixsec update---Bring work tree in sync with repository
@cindex Update (subcommand)

@itemize @bullet
@item
update [-AdflPpR] [-d] [-r tag|-D date] files@dots{}
@item
Requires: repository, working directory.
@item
Changes: working directory.
@end itemize

After you've run checkout to create your private copy
of source from the common repository, other developers
will continue changing the central source.  From time
to time, when it is convenient in your development
process, you can use the @code{update} command from
within your working directory to reconcile your work
with any revisions applied to the source repository
since your last checkout or update.

@menu
* update options::              update options
* update output::               update output
* update examples::             update examples
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node update options
@appendixsubsec update options

These standard options are available with @code{update}
(@pxref{Common options}, for a complete description of
them):

@table @code
@item -D date
Use the most recent revision no later than @var{date}.
This option is sticky, and implies @samp{-P}.
See @ref{Sticky tags}, for more information on sticky tags/dates.

@item -f
Only useful with the @samp{-D @var{date}} or @samp{-r
@var{tag}} flags.  If no matching revision is found,
retrieve the most recent revision (instead of ignoring
the file).

@item -k @var{kflag}
Process @sc{rcs} keywords according to @var{kflag}.  See
co(1).  This option is sticky; future updates of
this file in this working directory will use the same
@var{kflag}.  The @code{status} command can be viewed
to see the sticky options.  @xref{status}.

@item -l
Local; run only in current working directory.  @xref{Recursive behavior}.

@item -P
Prune empty directories.

@item -p
Pipe files to the standard output.

@item -R
Operate recursively.  This is on by default.
@xref{Recursive behavior}.

@item -r tag
Retrieve revision @var{tag}.  This option is sticky,
and implies @samp{-P}.
See @ref{Sticky tags}, for more information on sticky tags/dates.
@end table

@need 800
These special options are also available with
@code{update}.

@table @code
@item -A
Reset any sticky tags, dates, or @samp{-k} options.
See @ref{Sticky tags}, for more information on sticky tags/dates.

@item -d
Create any directories that exist in the repository if
they're missing from the working directory.  Normally,
@code{update} acts only on directories and files that
were already enrolled in your working directory.  

This is useful for updating directories that were
created in the repository since the initial checkout;
but it has an unfortunate side effect.  If you
deliberately avoided certain directories in the
repository when you created your working directory
(either through use of a module name or by listing
explicitly the files and directories you wanted on the
command line), then updating with @samp{-d} will create
those directories, which may not be what you want.

@item -I @var{name}
Ignore files whose names match @var{name} (in your
working directory) during the update.  You can specify
@samp{-I} more than once on the command line to specify
several files to ignore.  Use @samp{-I !} to avoid
ignoring any files at all.  @xref{cvsignore}, for other
ways to make @sc{cvs} ignore some files.

@item -W@var{spec}
Specify file names that should be filtered during
update.  You can use this option repeatedly.

@var{spec} can be a file name pattern of the same type
that you can specify in the @file{.cvswrappers}
file. @xref{Wrappers}.

@item -j@var{revision}
With two @samp{-j} options, merge changes from the
revision specified with the first @samp{-j} option to
the revision specified with the second @samp{j} option,
into the working directory.

With one @samp{-j} option, merge changes from the
ancestor revision to the revision specified with the
@samp{-j} option, into the working directory.  The
ancestor revision is the common ancestor of the
revision which the working directory is based on, and
the revision specified in the @samp{-j} option.

In addition, each -j option can contain an optional
date specification which, when used with branches, can
limit the chosen revision to one within a specific
date.  An optional date is specified by adding a colon
(:) to the tag:
@samp{-j@var{Symbolic_Tag}:@var{Date_Specifier}}.

@xref{Merging}.

@end table

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node update output
@appendixsubsec update output

@code{update} keeps you informed of its progress by
printing a line for each file, preceded by one
character indicating the status of the file:

@table @code
@item U @var{file}
The file was brought up to date with respect to the
repository.  This is done for any file that exists in
the repository but not in your source, and for files
that you haven't changed but are not the most recent
versions available in the repository.

@item A @var{file}
The file has been added to your private copy of the
sources, and will be added to the source repository
when you run @code{commit} on the file.  This is a
reminder to you that the file needs to be committed.

@item R @var{file}
The file has been removed from your private copy of the
sources, and will be removed from the source repository
when you run @code{commit} on the file.  This is a
reminder to you that the file needs to be committed.

@item M @var{file}
The file is modified in  your  working  directory.

@samp{M} can indicate one of two states for a file
you're working on: either there were no modifications
to the same file in the repository, so that your file
remains as you last saw it; or there were modifications
in the repository as well as in your copy, but they
were merged successfully, without conflict, in your
working directory.

@sc{cvs} will print some messages if it merges your work,
and a backup copy of your working file (as it looked
before you ran @code{update}) will be made.  The exact
name of that file is printed while @code{update} runs.

@item C @var{file}
A conflict was detected while trying to merge your
changes to @var{file} with changes from the source
repository.  @var{file} (the copy in your working
directory) is now the output of the rcsmerge(1) command
on the two revisions; an unmodified copy of your file
is also in your working directory, with the name
@file{.#@var{file}.@var{revision}} where @var{revision}
is the @sc{rcs} revision that your modified file started
from.  (Note that some systems automatically purge
files that begin with @file{.#} if they have not been
accessed for a few days.  If you intend to keep a copy
of your original file, it is a very good idea to rename
it.)

@item ? @var{file}
@var{file} is in your working directory, but does not
correspond to anything in the source repository, and is
not in the list of files for @sc{cvs} to ignore (see the
description of the @samp{-I} option, and
@pxref{cvsignore}).

Note that no warning message like this is printed for
spurious directories that @sc{cvs} encounters.  The
directory, and all its contents, are silently ignored.
@end table

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node update examples
@appendixsubsec update examples

The following line will display all files which are not
up-to-date without actually change anything in your
working directory.  It can be used to check what has
been going on with the project.

@example
$ cvs -n -q update
@end example

@c ---------------------------------------------------------------------
@node Administrative files
@appendix Reference manual for the Administrative files
@cindex Administrative files (reference)
@cindex Files, reference manual
@cindex Reference manual (files)
@cindex CVSROOT (file)

Inside the repository, in the directory
@file{$CVSROOT/CVSROOT}, there are a number of
supportive files for @sc{cvs}.  You can use @sc{cvs} in a limited
fashion without any of them, but if they are set up
properly they can help make life easier.

The most important of these files is the @file{modules}
file, which defines the modules inside the repository.

@menu
* modules::                     Defining modules
* Wrappers::                    Treat directories as files
* commit files::                The commit support files
* commitinfo::                  Pre-commit checking
* editinfo::                    Specifying how log messages are created
* loginfo::                     Where should log messages be sent?
* rcsinfo::                     Templates for the log messages
* cvsignore::                   Ignoring files via cvsignore
* history file::                History information
* Setting up::                  Setting up the repository
* Variables::                   Various variables are expanded
@end menu

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node modules
@appendixsec The modules file
@cindex Modules (admin file)
@cindex Defining modules (reference manual)

The @file{modules} file records your definitions of
names for collections of source code.  @sc{cvs} will
use these definitions if you use @sc{cvs} to update the
modules file (use normal commands like @code{add},
@code{commit}, etc).

The @file{modules} file may contain blank lines and
comments (lines beginning with @samp{#}) as well as
module definitions.  Long lines can be continued on the
next line by specifying a backslash (@samp{\}) as the
last character on the line.

A module definition is a single line of the
@file{modules} file, in either of two formats.  In both
cases, @var{mname} represents the symbolic module name,
and the remainder of the line is its definition.

@table @code
@item @var{mname} -a @var{aliases}@dots{}
This represents the simplest way of defining a module
@var{mname}.  The @samp{-a} flags the definition as a
simple alias: @sc{cvs} will treat any use of @var{mname} (as
a command argument) as if the list of names
@var{aliases} had been specified instead.
@var{aliases} may contain either other module names or
paths.  When you use paths in aliases, @code{checkout}
creates all intermediate directories in the working
directory, just as if the path had been specified
explicitly in the @sc{cvs} arguments.

@item @var{mname} [ options ] @var{dir} [ @var{files}@dots{} ] [ &@var{module}@dots{} ]
In the simplest case, this form of module definition
reduces to @samp{@var{mname} @var{dir}}.  This defines
all the files in directory @var{dir} as module mname.
@var{dir} is a relative path (from @code{$CVSROOT}) to a
directory of source in the source repository.  In this
case, on checkout, a single directory called
@var{mname} is created as a working directory; no
intermediate directory levels are used by default, even
if @var{dir} was a path involving several directory
levels.

By explicitly specifying files in the module definition
after @var{dir}, you can select particular files from
directory @var{dir}.  The sample definition for
@samp{modules} is an example of a module defined with a
single file from a particular directory.  Here is
another example:

@example
m4test  unsupported/gnu/m4 foreach.m4 forloop.m4
@end example

@noindent
With this definition, executing @samp{cvs checkout
m4test} will create a single working directory
@file{m4test} containing the two files listed, which
both come from a common directory several levels deep
in the @sc{cvs} source repository.

A module definition can refer to other modules by
including @samp{&@var{module}} in its definition.
@code{checkout} creates a subdirectory for each such
module, in your working directory.
@c -- Nope. "in your working directory" is wrong. What
@c -- is right?

@table @code
@item -d @var{name}
Name the working directory something other than the
module name.

@cindex Export program
@item -e @var{prog}
Specify a program @var{prog} to run whenever files in a
module are exported.  @var{prog} runs with a single
argument, the module name.

@cindex Checkin program
@item -i @var{prog}
Specify a program @var{prog} to run whenever files in a
module are committed.  @var{prog} runs with a single
argument, the full pathname of the affected directory
in a source repository.  The @file{commitinfo},
@file{loginfo}, and @file{editinfo} files provide other
ways to call a program on commit.

@cindex Checkout program
@item -o @var{prog}
Specify a program @var{prog} to run whenever files in a
module are checked out.  @var{prog} runs with a single
argument, the module name.

@cindex Status of a module
@cindex Module status
@item -s @var{status}
Assign a status to the module.  When the module file is
printed with @samp{cvs checkout -s} the modules are
sorted according to primarily module status, and
secondarily according to the module name.  This option
has no other meaning.  You can use this option for
several things besides status: for instance, list the
person that is responsible for this module.

@cindex Tag program
@item -t @var{prog}
Specify a program @var{prog} to run whenever files in a
module are tagged with @code{rtag}.  @var{prog} runs
with two arguments: the module name and the symbolic
tag specified to @code{rtag}.  There is no way to
specify a program to run when @code{tag} is executed.

@cindex Update program
@item -u @var{prog}
Specify a program @var{prog} to run whenever @samp{cvs
update} is executed from the top-level directory of the
checked-out module.  @var{prog} runs with a single
argument, the full path to the source repository for
this module.
@end table
@end table

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Wrappers
@appendixsec The cvswrappers file
@cindex cvswrappers (admin file)
@cindex CVSWRAPPERS, environment variable
@cindex Wrappers

Wrappers allow you to set a hook which transforms files on
their way in and out of @sc{cvs}.  Most or all of the
wrappers features do not work with client/server @sc{cvs}.

The file @file{cvswrappers} defines the script that will be
run on a file when its name matches a regular
expresion. There are two scripts that can be run on a
file or directory. One script is executed on the file/directory
before being checked into the repository (this is denoted
with the @code{-t} flag) and the other when the file is
checked out of the repository (this is denoted with the
@code{-f} flag)

The @file{cvswrappers} also has a @samp{-m} option to
specify the merge methodology that should be used when
the file is updated.  @code{MERGE} means the usual
@sc{cvs} behavior: try to merge the files (this
generally will not work for binary files).  @code{COPY}
means that @code{cvs update} will merely copy one
version over the other, and require the user using
mechanisms outside @sc{cvs}, to insert any necessary
changes.
@c FIXME: which version is copied over which version?
The @samp{-m} wrapper option only affects behavior when
merging is done on update; it does not affect how files
are stored.  See @xref{Binary files}, for more on
binary files.

The basic format of the file @file{cvswrappers} is:

@example
wildcard     [option value][option value]...

where option is one of
-f           from cvs filter         value: path tofilter
-t           to cvs filter           value: path to filter
-m           update methodology      value: MERGE or COPY

and value is a single-quote delimited value.
@end example

@example
*.nib    -f 'unwrap %s' -t 'wrap %s %s' -m 'COPY'
*.c      -t 'indent %s %s'
@end example

@noindent
The above example of a @file{cvswrappers} file
states that all files/directories that end with a @code{.nib}
should be filtered with the @file{wrap} program before
checking the file into the repository. The file should
be filtered though the @file{unwrap} program when the
file is checked out of the repository. The
@file{cvswrappers} file also states that a @code{COPY}
methodology should be used when updating the files in
the repository (that is no merging should be performed).

The last example line says that all files that end with
a @code{*.c} should be filtered with @file{indent}
before being checked into the repository. Unlike the previous
example no filtering of the @code{*.c} file is done when
it is checked out of the repository.
@noindent
The @code{-t} filter is called with two arguments,
the first is the name of the file/directory to filter
and the second is the pathname to where the resulting
filtered file should be placed.

@noindent
The @code{-f} filter is called with one argument,
which is the name of the file to filter from. The end
result of this filter will be a file in the users directory
that they can work on as they normally would.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node commit files
@appendixsec The commit support files
@cindex Commit files

The @samp{-i} flag in the @file{modules} file can be
used to run a certain program whenever files are
committed (@pxref{modules}).  The files described in
this section provide other, more flexible, ways to run
programs whenever something is committed.

There are three kind of programs that can be run on
commit.  They are specified in files in the repository,
as described below.  The following table summarizes the
file names and the purpose of the corresponding
programs.

@table @file
@item commitinfo
The program is responsible for checking that the commit
is allowed.  If it exits with a non-zero exit status
the commit will be aborted.

@item editinfo
The specified program is used to edit the log message,
and possibly verify that it contains all required
fields.  This is most useful in combination with the
@file{rcsinfo} file, which can hold a log message
template (@pxref{rcsinfo}).

@item loginfo
The specified program is called when the commit is
complete.  It receives the log message and some
additional information and can store the log message in
a file, or mail it to appropriate persons, or maybe
post it to a local newsgroup, or@dots{}  Your
imagination is the limit!
@end table

@menu
* syntax::                      The common syntax
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node syntax
@appendixsubsec The common syntax
@cindex Info files (syntax)
@cindex Syntax of info files
@cindex Common syntax of info files

The four files @file{commitinfo}, @file{loginfo},
@file{rcsinfo} and @file{editinfo} all have a common
format.  The purpose of the files are described later
on.  The common syntax is described here.

Each line contains the following:
@itemize @bullet
@item
A regular expression

@item
A whitespace separator---one or more spaces and/or tabs.

@item
A file name or command-line template.
@end itemize

@noindent
Blank lines are ignored.  Lines that start with the
character @samp{#} are treated as comments.  Long lines
unfortunately can @emph{not} be broken in two parts in
any way.

The first regular expression that matches the current
directory name in the repository is used.  The rest of the line
is used as a file name or command-line as appropriate.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node commitinfo
@appendixsec Commitinfo
@cindex Commitinfo
@cindex Checking commits
@cindex Precommit checking

The @file{commitinfo} file defines programs to execute
whenever @samp{cvs commit} is about to execute.  These
programs are used for pre-commit checking to verify
that the modified, added and removed files are really
ready to be committed.  This could be used, for
instance, to verify that the changed files conform to
to your site's standards for coding practice.

As mentioned earlier, each line in the
@file{commitinfo} file consists of a regular expression
and a command-line template.  The template can include
a program name and any number of arguments you wish to
supply to it.  The full path to the current source
repository is appended to the template, followed by the
file names of any files involved in the commit (added,
removed, and modified files).

The first line with a regular expression matching the
relative path to the module will be used.  If the
command returns a non-zero exit status the commit will
be aborted.

@cindex DEFAULT in commitinfo
If the repository name does not match any of the
regular expressions in this file, the @samp{DEFAULT}
line is used, if it is specified.

@cindex ALL in commitinfo
All occurances of the name @samp{ALL} appearing as a
regular expression are used in addition to the first
matching regular expression or the name @samp{DEFAULT}.

Note: when @sc{CVS} is accessing a remote repository,
@file{commitinfo} will be run on the @emph{remote}
(i.e., server) side, not the client side (@pxref{Remote
repositories}).

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node editinfo
@appendixsec Editinfo
@cindex Editinfo
@cindex Editor, specifying per module
@cindex Per-module editor
@cindex Log messages, editing

If you want to make sure that all log messages look the
same way, you can use the @file{editinfo} file to
specify a program that is used to edit the log message.
This program could be a custom-made editor that always
enforces a certain style of the log message, or maybe a
simple shell script that calls an editor, and checks
that the entered message contains the required fields.

If no matching line is found in the @file{editinfo}
file, the editor specified in the environment variable
@code{$CVSEDITOR} is used instead.  If that variable is
not set, then the environment variable @code{$EDITOR}
is used instead.  If that variable is not
set a precompiled default, normally @code{vi}, will be
used.

The @file{editinfo} file is often most useful together
with the @file{rcsinfo} file, which can be used to
specify a log message template.

Each line in the @file{editinfo} file consists of a
regular expression and a command-line template.  The
template must include a program name, and can include
any number of arguments.  The full path to the current
log message template file is appended to the template.

One thing that should be noted is that the @samp{ALL}
keyword is not supported.  If more than one matching
line is found, the first one is used.  This can be
useful for specifying a default edit script in a
module, and then overriding it in a subdirectory.

@cindex DEFAULT in editinfo
If the repository name does not match any of the
regular expressions in this file, the @samp{DEFAULT}
line is used, if it is specified.

If the edit script exits with a non-zero exit status,
the commit is aborted.

Note: when @sc{CVS} is accessing a remote repository,
@file{editinfo} will be run on the @emph{remote}
(i.e., server) side, not the client side (@pxref{Remote
repositories}).

@menu
* editinfo example::            Editinfo example
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node editinfo example
@appendixsubsec Editinfo example

The following is a little silly example of a
@file{editinfo} file, together with the corresponding
@file{rcsinfo} file, the log message template and an
editor script.  We begin with the log message template.
We want to always record a bug-id number on the first
line of the log message.  The rest of log message is
free text.  The following template is found in the file
@file{/usr/cvssupport/tc.template}.

@example
BugId:    
@end example

The script @file{/usr/cvssupport/bugid.edit} is used to
edit the log message.

@example
#!/bin/sh
#
#       bugid.edit filename
#
#  Call $EDITOR on FILENAME, and verify that the
#  resulting file contains a valid bugid on the first
#  line.
if [ "x$EDITOR" = "x" ]; then EDITOR=vi; fi
if [ "x$CVSEDITOR" = "x" ]; then CVSEDITOR=$EDITOR; fi
$CVSEDITOR $1
until head -1|grep '^BugId:[ ]*[0-9][0-9]*$' < $1
do  echo -n  "No BugId found.  Edit again? ([y]/n)"
    read ans
    case $@{ans@} in
        n*) exit 1;;
    esac
    $CVSEDITOR $1
done
@end example

The @file{editinfo} file contains this line:

@example
^tc     /usr/cvssupport/bugid.edit
@end example

The @file{rcsinfo} file contains this line:

@example
^tc     /usr/cvssupport/tc.template
@end example

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node loginfo
@appendixsec Loginfo
@cindex Loginfo
@cindex Storing log messages
@cindex Mailing log messages
@cindex Distributing log messages
@cindex Log messages

The @file{loginfo} file is used to control where
@samp{cvs commit} log information is sent.  The first
entry on a line is a regular expression which is tested
against the directory that the change is being made to,
relative to the @code{$CVSROOT}.  If a match is found, then
the remainder of the line is a filter program that
should expect log information on its standard input.

The filter program may use one and only one % modifier
(a la printf).  If @samp{%s} is specified in the filter
program, a brief title is included (enclosed in single
quotes) showing the modified file names.

If the repository name does not match any of the
regular expressions in this file, the @samp{DEFAULT}
line is used, if it is specified.

All occurances of the name @samp{ALL} appearing as a
regular expression are used in addition to the first
matching regular expression or @samp{DEFAULT}.

The first matching regular expression is used.

@xref{commit files}, for a description of the syntax of
the @file{loginfo} file.  

Note: when @sc{CVS} is accessing a remote repository,
@file{loginfo} will be run on the @emph{remote}
(i.e., server) side, not the client side (@pxref{Remote
repositories}).

@menu
* loginfo example::             Loginfo example
@end menu

@c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
@node loginfo example
@appendixsubsec Loginfo example

The following @file{loginfo} file, together with the
tiny shell-script below, appends all log messages 
to the file @file{$CVSROOT/CVSROOT/commitlog},
and any commits to the administrative files (inside
the @file{CVSROOT} directory) are also logged in
@file{/usr/adm/cvsroot-log}.
@c and mailed to @t{ceder}.

@c FIXME: is it a CVS feature or bug that only the
@c first matching line is used?  It is documented
@c above, but is it useful?  This example (with the
@c mail to ceder put back in) is awkward to write if
@c only the first matching line is used.
@example
ALL             /usr/local/bin/cvs-log $CVSROOT/CVSROOT/commitlog
@c ^CVSROOT        Mail -s %s ceder
^CVSROOT        /usr/local/bin/cvs-log /usr/adm/cvsroot-log
@end example

The shell-script @file{/usr/local/bin/cvs-log} looks
like this:

@example
#!/bin/sh
(echo "-----------------------------------------------------------------";
 echo -n $USER"  ";
 date;
 echo;
 sed '1s+'$@{CVSROOT@}'++') >> $1
@end example

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node rcsinfo
@appendixsec Rcsinfo
@cindex Rcsinfo
@cindex Form for log message
@cindex Log message template
@cindex Template for log message

The @file{rcsinfo} file can be used to specify a form to
edit when filling out the commit log.  The
@file{rcsinfo} file has a syntax similar to the
@file{editinfo}, @file{commitinfo} and @file{loginfo}
files.  @xref{syntax}.  Unlike the other files the second
part is @emph{not} a command-line template.  Instead,
the part after the regular expression should be a full pathname to
a file containing the log message template.

If the repository name does not match any of the
regular expressions in this file, the @samp{DEFAULT}
line is used, if it is specified.

All occurances of the name @samp{ALL} appearing as a
regular expression are used in addition to the first
matching regular expression or @samp{DEFAULT}.

The log message template will be used as a default log
message.  If you specify a log message with @samp{cvs
commit -m @var{message}} or @samp{cvs commit -f
@var{file}} that log message will override the
template.

@xref{editinfo example}, for an example @file{rcsinfo}
file.

When @sc{CVS} is accessing a remote repository,
the contents of @file{rcsinfo} at the time a directory
is first checked out will specify a template which does
not then change.  If you edit @file{rcsinfo} or its
templates, you may need to check out a new working
directory.
@c Would be nice to fix CVS so this isn't needed.  For
@c example, a mechanism analogous to CVS/Entries, where
@c the client keeps track of what version of the template
@c it has.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node cvsignore
@appendixsec Ignoring files via cvsignore
@cindex Cvsignore, global
@cindex Global cvsignore
@cindex Ignoring files
@c -- This chapter should maybe be moved to the
@c tutorial part of the manual?

There are certain file names that frequently occur
inside your working copy, but that you don't want to
put under @sc{cvs} control.  Examples are all the object
files that you get while you compile your sources.
Normally, when you run @samp{cvs update}, it prints a
line for each file it encounters that it doesn't know
about (@pxref{update output}).

@sc{cvs} has a list of files (or sh(1) file name patterns)
that it should ignore while running @code{update},
@code{import} and @code{release}.
@c -- Are those the only three commands affected?
This list is constructed in the following way.

@itemize @bullet
@item
The list is initialized to include certain file name
patterns: names associated with @sc{cvs}
administration, or with other common source control
systems; common names for patch files, object files,
archive files, and editor backup files; and other names
that are usually artifacts of assorted utilities.
Currently, the default list of ignored file name
patterns is:

@cindex Ignored files
@cindex Automatically ignored files
@example
    RCS     SCCS    CVS     CVS.adm
    RCSLOG  cvslog.*
    tags    TAGS
    .make.state     .nse_depinfo
    *~      #*      .#*     ,*      _$*     *$
    *.old   *.bak   *.BAK   *.orig  *.rej   .del-*
    *.a     *.olb   *.o     *.obj   *.so    *.exe
    *.Z     *.elc   *.ln  
    core
@end example

@item
The per-repository list in
@file{$CVSROOT/CVSROOT/cvsignore} is appended to
the list, if that file exists.

@item
The per-user list in @file{.cvsignore} in your home
directory is appended to the list, if it exists.

@item
Any entries in the environment variable
@code{$CVSIGNORE} is appended to the list.

@item
Any @samp{-I} options given to @sc{cvs} is appended.

@item
As @sc{cvs} traverses through your directories, the contents
of any @file{.cvsignore} will be appended to the list.
The patterns found in @file{.cvsignore} are only valid
for the directory that contains them, not for
any sub-directories.
@end itemize

In any of the 5 places listed above, a single
exclamation mark (@samp{!}) clears the ignore list.
This can be used if you want to store any file which
normally is ignored by @sc{cvs}.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node history file
@appendixsec The history file
@cindex History file
@cindex Log information, saving

The file @file{$CVSROOT/CVSROOT/history} is used
to log information for the @code{history} command
(@pxref{history}).  This file must be created to turn
on logging.  This is done automatically if the
@code{cvs init} command is used to set up the
repository (@pxref{Setting up}).

The file format of the @file{history} file is
documented only in comments in the @sc{cvs} source
code, but generally programs should use the @code{cvs
history} command to access it anyway, in case the
format changes with future releases of @sc{cvs}.

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Setting up
@appendixsec Setting up the repository 
@cindex Repository, setting up
@cindex Creating a repository
@cindex Setting up a repository

To set up a @sc{cvs} repository, choose a directory
with ample disk space available for the revision
history of the source files.  It should be accessable
(directly or via a networked file system) from all
machines which want to use @sc{cvs} in server or local
mode; the client machines need not have any access to
it other than via the @sc{cvs} protocol.

To create a repository, run the @code{cvs init}
command.  It will set up an empty repository in the
@sc{cvs} root specified in the usual way
(@pxref{Repository}).  For example,

@example
cvs -d /usr/local/cvsroot init
@end example

@code{cvs init} is careful to never overwrite any
existing files in the repository, so no harm is done if
you run @code{cvs init} on an already set-up
repository.

@code{cvs init} will enable history logging; if you
don't want that, remove the history file after running
@code{cvs init}.  @xref{history file}.

@node Variables
@appendixsec Expansions in administrative files

Sometimes in writing an administrative file, you might
want the file to be able to know various things based
on environment @sc{cvs} is running in.  There are
several mechanisms to do that.

To find the home directory of the user running @sc{cvs}
(from the @code{HOME} environment variable), use
@samp{~} followed by @samp{/} or the end of the line.
Likewise for the home directory of @var{user}, use
@samp{~@var{user}}.  These variables are expanded on
the server machine, and don't get any resonable
expansion if pserver (@pxref{Password authenticated})
is in used; therefore user variables (see below) may be
a better choice to customize behavior based on the user
running @sc{cvs}.
@c Based on these limitations, should we deprecate ~?
@c What is it good for?  Are people using it?

One may want to know about various pieces of
information internal to @sc{cvs}.  A @sc{cvs} internal
variable has the syntax @code{$@{@var{variable}@}},
where @var{variable} starts with a letter and consists
of alphanumberic characters and @samp{_}.  If the
character following @var{variable} is a
non-alphanumeric character other than @samp{_}, the
@samp{@{} and @samp{@}} can be omitted.  The @sc{cvs}
internal variables are:

@table @code
@item CVSROOT
This is the value of the @sc{cvs} root in use.
@xref{Repository}, for a description of the various
ways to specify this.

@item RCSBIN
This is the value @sc{cvs} is using for where to find
@sc{rcs} binaries.  @xref{Global options}, for a
description of how to specify this.

@item CVSEDITOR
@itemx VISUAL
@itemx EDITOR
These all expand to the same value, which is the editor
that @sc{cvs} is using.  @xref{Global options}, for how
to specify this.

@item USER
Username of the user running @sc{cvs} (on the @sc{cvs}
server machine).
@end table

If you want to pass a value to the administrative files
which the user that is running @sc{cvs} can specify,
use a user variable.  To expand a user variable, the
administrative file contains
@code{$@{=@var{variable}@}}.  To set a user variable,
specify the global option @samp{-s} to @sc{cvs}, with
argument @code{@var{variable}=@var{value}}.  It may be
particularly useful to specify this option via
@file{.cvsrc} (@pxref{~/.cvsrc}).

For example, if you want the administrative file to
refer to a test directory you might create a user
variable @code{TESTDIR}.  Then if @sc{cvs} is invoked
as @code{cvs -s TESTDIR=/work/local/tests}, and the
administrative file contains @code{sh
$@{=TESTDIR@}/runtests}, then that string is expanded
to @code{sh /work/local/tests/runtests}.

All other strings containing @samp{$} are reserved;
there is no way to quote a @samp{$} character so that
@samp{$} represents itself.

@c ---------------------------------------------------------------------
@node Environment variables
@appendix All environment variables which affect CVS
@cindex Environment variables
@cindex Reference manual for variables

This is a complete list of all environment variables
that affect @sc{cvs}.

@table @code
@cindex CVSIGNORE
@item $CVSIGNORE
A whitespace-separated list of file name patterns that
@sc{cvs} should ignore. @xref{cvsignore}.

@cindex CVSWRAPPERS
@item $CVSWRAPPERS
A whitespace-separated list of file name patterns that
@sc{cvs} should treat as wrappers. @xref{Wrappers}.

@cindex CVSREAD
@item $CVSREAD
If this is set, @code{checkout} and @code{update} will
try hard to make the files in your working directory
read-only.  When this is not set, the default behavior
is to permit modification of your working files.

@cindex CVSROOT
@item $CVSROOT
Should contain the full pathname to the root of the @sc{cvs}
source repository (where the @sc{rcs} history files are
kept).  This information must be available to @sc{cvs} for
most commands to execute; if @code{$CVSROOT} is not set,
or if you wish to override it for one invocation, you
can supply it on the command line: @samp{cvs -d cvsroot
cvs_command@dots{}} Once you have checked out a working
directory, @sc{cvs} stores the appropriate root (in
the file @file{CVS/Root}), so normally you only need to
worry about this when initially checking out a working 
directory.

@cindex EDITOR
@cindex CVSEDITOR
@item $EDITOR
@itemx $CVSEDITOR
Specifies the program to use for recording log messages
during commit.  If not set, the default is
@samp{/usr/ucb/vi}.  @code{$CVSEDITOR} overrides
@code{$EDITOR}.  @code{$CVSEDITOR} does not exist in
@sc{cvs} 1.3, but the next release will probably
include it.

@cindex PATH
@item $PATH
If @code{$RCSBIN} is not set, and no path is compiled
into @sc{cvs}, it will use @code{$PATH} to try to find all
programs it uses.

@cindex RCSBIN
@item $RCSBIN
Specifies the full pathname of the location of @sc{rcs} programs,
such as co(1) and ci(1).  If not set, a compiled-in
value is used, or your @code{$PATH} is searched.

@cindex HOME
@item $HOME
@cindex HOMEPATH
@item $HOMEPATH
Used to locate the directory where the @file{.cvsrc}
file is searched (@code{$HOMEPATH} is used for Windows-NT).
@pxref{~/.cvsrc}

@cindex CVS_RSH
@item $CVS_RSH
Used in client-server mode when accessing a remote
repository using @sc{rsh}.  The default value is
@code{rsh}.  You can set it to use another program for
accssing the remote server (e.g. for HP-UX 9, you
should set it to @code{remsh} because @code{rsh}
invokes the restricted shell).  @pxref{Connecting via
rsh}

@item $CVS_SERVER
Used in client-server mode when accessing a remote
repository using @sc{rsh}.  It specifies the name of
the program to start on the server side when accessing
a remote repository using @sc{rsh}.  The default value
is @code{cvs}.  @pxref{Connecting via rsh}

@item $CVS_PASSFILE
Used in client-server mode when accessing the @code{cvs
login server}.  Default value is @file{$HOME/.cvspass}.
@pxref{Password authentication client}

@item $CVS_PASSWORD
Used in client-server mode when accessing the @code{cvs
login server}.
@pxref{Password authentication client}

@item $CVS_CLIENT_PORT
Used in client-server mode when accessing the server
via Kerberos.
@pxref{Kerberos authenticated}

@cindex CVS_RCMD_PORT
@item $CVS_RCMD_PORT
Used in client-server mode.  If set, specifies the port
number to be used when accessing the @sc{rcmd} demon on
the server side. (Currently not used for Unix clients).

@cindex CVS_CLIENT_LOG
@item $CVS_CLIENT_LOG
Used for debugging only in client-server
mode.  If set, everything send to the server is logged
into @file{@code{$CVS_CLIENT_LOG}.in} and everything
send from the server is logged into
@file{@code{$CVS_CLIENT_LOG}.out}.

@cindex CVS_SERVER_SLEEP
@item $CVS_SERVER_SLEEP
Used only for debugging the server side in
client-server mode.  If set, delays the start of the
server child process the the specified amount of
seconds so that you can attach to it with a debugger.

@cindex CVS_IGNORE_REMOTE_ROOT
@item $CVS_IGNORE_REMOTE_ROOT
(What is the purpose of this variable?)

@cindex COMSPEC
@item $COMSPEC
Used under OS/2 only.  It specifies the name of the
command interpreter and defaults to @sc{cmd.exe}.


@end table

@sc{cvs} is a front-end to @sc{rcs}.  The following environment
variables affect @sc{rcs}.  Note that if you are using
the client/server @sc{cvs}, these variables need to be
set on the server side (which may or not may be
possible depending on how you are connecting).  There
is probably not any need to set any of them, however.

@table @code
@cindex LOGNAME
@item $LOGNAME
@cindex USER
@itemx $USER
If set, they affect who @sc{rcs} thinks you are.  If you
have trouble checking in files it might be because your
login name differs from the setting of e.g.
@code{$LOGNAME}.

@cindex RCSINIT
@item $RCSINIT
Options prepended to the argument list, separated by
spaces.  A backslash escapes spaces within an option.
The @code{$RCSINIT} options are prepended to the
argument lists of most @sc{rcs} commands.

@cindex TMPDIR
@item $TMPDIR
@cindex TMP
@itemx $TMP
@cindex TEMP
@itemx $TEMP
Name of the temporary directory.  The environment
variables are inspected in the order they appear above
and the first value found is taken; if none of them are
set, a host-dependent default is used, typically
@file{/tmp}.
@end table

@c ---------------------------------------------------------------------
@node Troubleshooting
@appendix Troubleshooting

@menu
* Magic branch numbers::        Magic branch numbers
@end menu

@ignore
@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@c @node Bad administrative files
@appendixsec Bad administrative files

@c -- Give hints on how to fix them
@end ignore

@c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@node Magic branch numbers
@appendixsec Magic branch numbers

Externally, branch numbers consist of an odd number of
dot-separated decimal integers.  @xref{Revision
numbers}.  That is not the whole truth, however.  For
efficiency reasons @sc{cvs} sometimes inserts an extra 0
in the second rightmost position (1.2.3 becomes
1.2.0.3, 8.9.10.11.12 becomes 8.9.10.11.0.12 and so
on).

@sc{cvs} does a pretty good job at hiding these so
called magic branches, but in at least four places the
hiding is incomplete.

@itemize @bullet
@item
The magic branch can appear in the output from
@code{cvs status} in vanilla @sc{cvs} 1.3.  This is
fixed in @sc{cvs} 1.3-s2.

@item
The magic branch number appears in the output from
@code{cvs log}.  This is much harder to fix, since
@code{cvs log} runs @code{rlog} (which is part of the
@sc{rcs} distribution), and modifying @code{rlog} to
know about magic branches would probably break someone's
habits (if they use branch 0 for their own purposes).

@item
You cannot specify a symbolic branch name to @code{cvs log}.

@item
You cannot specify a symbolic branch name to @code{cvs
admin}.

@end itemize

You can use the @code{admin} command to reassign a
symbolic name to a branch the way @sc{rcs} expects it
to be.  If @code{R4patches} is assigned to the branch
1.4.2 (magic branch number 1.4.0.2) in file
@file{numbers.c} you can do this:

@example
$ cvs admin -NR4patches:1.4.2 numbers.c
@end example

It only works if at least one revision is already
committed on the branch.  Be very careful so that you
do not assign the tag to the wrong number.  (There is
no way to see how the tag was assigned yesterday).

@c ---------------------------------------------------------------------
@node Copying
@appendix GNU GENERAL PUBLIC LICENSE
@c @include gpl.texinfo

@c ---------------------------------------------------------------------
@node Index
@unnumbered Index
@cindex Index

@printindex cp

@summarycontents

@contents

@bye

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