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(Startup Summary): Correct the options; add missing ones.
(Terminal Output, Batch Mode): Clarify. (Flow Control): Node deleted.
This commit is contained in:
Richard M. Stallman
parent
be2bd2c2da
commit
9775b55021
182
lispref/os.texi
182
lispref/os.texi
@ -30,7 +30,6 @@ pertaining to the terminal and the screen.
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* Terminal Output:: Recording terminal output for debugging.
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* Sound Output:: Playing sounds on the computer's speaker.
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* X11 Keysyms:: Operating on key symbols for X Windows
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* Flow Control:: How to turn output flow control on or off.
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* Batch Mode:: Running Emacs without terminal interaction.
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* Session Management:: Saving and restoring state with X Session Management.
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@end menu
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@ -86,22 +85,22 @@ It initializes the window frame and faces, if appropriate.
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It runs the normal hook @code{before-init-hook}.
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@item
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It loads the library @file{site-start}, unless the option
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@samp{-no-site-file} was specified. The library's file name is usually
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@file{site-start.el}.
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It loads the library @file{site-start} (if any), unless the option
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@samp{-Q} (or @samp{--no-site-file}) was specified. The library's file
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name is usually @file{site-start.el}.
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@cindex @file{site-start.el}
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@item
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It loads your init file (usually @file{~/.emacs}), unless @samp{-q},
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@samp{-no-init-file}, or @samp{-batch} was specified on the command line.
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The @samp{-u} option can specify another user whose home directory
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should be used instead of @file{~}.
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It loads your init file (usually @file{~/.emacs}), unless @samp{-q}
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(or @samp{--no-init-file}), @samp{-Q}, or @samp{--batch} was specified
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on the command line. The @samp{-u} option can specify another user
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whose home directory should be used instead of @file{~}.
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@item
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It loads the library @file{default}, unless @code{inhibit-default-init}
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is non-@code{nil}. (This is not done in @samp{-batch} mode or if
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@samp{-q} was specified on the command line.) The library's file name
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is usually @file{default.el}.
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It loads the library @file{default} (if any), unless
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@code{inhibit-default-init} is non-@code{nil}. (This is not done in
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@samp{-batch} mode, or if @samp{-Q} or @samp{-q} was specified on the
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command line.) The library's file name is usually @file{default.el}.
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@cindex @file{default.el}
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@item
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@ -118,7 +117,7 @@ mode or using a window system.
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@item
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It displays the initial echo area message, unless you have suppressed
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that with @code{inhibit-startup-echo-area-message}.
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that with @code{inhibit-startup-echo-area-message} or @samp{-Q}.
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@item
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It processes the action arguments from the command line.
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@ -136,9 +135,8 @@ It runs @code{window-setup-hook}. @xref{Window Systems}.
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@item
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It displays copyleft, nonwarranty, and basic use information, provided
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there were no remaining command-line arguments (a few steps above),
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the value of @code{inhibit-startup-message} is @code{nil}, and the
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buffer is still empty.
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the value of @code{inhibit-startup-message} is @code{nil}, you didn't
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specify @samp{--no-splash} or @samp{-Q}, and the buffer is still empty.
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@end enumerate
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@defopt inhibit-startup-message
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@ -179,36 +177,39 @@ for someone else.
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@cindex @file{.emacs}
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When you start Emacs, it normally attempts to load your @dfn{init
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file}, a file in your home directory. Its normal name is @file{.emacs},
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but you can alternatively call it @file{.emacs.el}, which enables you to
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byte-compile it (@pxref{Byte Compilation}); then the actual file loaded
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will be @file{.emacs.elc}.
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file}, a file in your home directory. Its normal name is
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@file{.emacs}, but you can alternatively call it @file{.emacs.el}.
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You can also store it inside a subdirectory @file{.emacs.d}.
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Whichever place you use, you can also compile the file (@pxref{Byte
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Compilation}); then the actual file loaded will be @file{.emacs.elc}.
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The command-line switches @samp{-q} and @samp{-u} control whether and
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where to find the init file; @samp{-q} says not to load an init file,
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and @samp{-u @var{user}} says to load @var{user}'s init file instead of
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yours. @xref{Entering Emacs,,, emacs, The GNU Emacs Manual}. If
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neither option is specified, Emacs uses the @code{LOGNAME} environment
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The command-line switches @samp{-q}, @samp{-Q}, and @samp{-u}
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control whether and where to find the init file; @samp{-q} (and the
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stronger @samp{-Q}) says not to load an init file, while @samp{-u
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@var{user}} says to load @var{user}'s init file instead of yours.
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@xref{Entering Emacs,,, emacs, The GNU Emacs Manual}. If neither
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option is specified, Emacs uses the @code{LOGNAME} environment
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variable, or the @code{USER} (most systems) or @code{USERNAME} (MS
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systems) variable, to find your home directory and thus your init file;
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this way, even if you have su'd, Emacs still loads your own init file.
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If those environment variables are absent, though, Emacs uses your
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user-id to find your home directory.
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systems) variable, to find your home directory and thus your init
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file; this way, even if you have su'd, Emacs still loads your own init
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file. If those environment variables are absent, though, Emacs uses
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your user-id to find your home directory.
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@cindex default init file
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A site may have a @dfn{default init file}, which is the library named
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@file{default.el}. Emacs finds the @file{default.el} file through the
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standard search path for libraries (@pxref{How Programs Do Loading}).
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The Emacs distribution does not come with this file; sites may provide
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one for local customizations. If the default init file exists, it is
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loaded whenever you start Emacs, except in batch mode or if @samp{-q} is
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specified. But your own personal init file, if any, is loaded first; if
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it sets @code{inhibit-default-init} to a non-@code{nil} value, then
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Emacs does not subsequently load the @file{default.el} file.
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A site may have a @dfn{default init file}, which is the library
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named @file{default.el}. Emacs finds the @file{default.el} file
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through the standard search path for libraries (@pxref{How Programs Do
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Loading}). The Emacs distribution does not come with this file; sites
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may provide one for local customizations. If the default init file
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exists, it is loaded whenever you start Emacs, except in batch mode or
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if @samp{-q} (or @samp{-Q}) is specified. But your own personal init
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file, if any, is loaded first; if it sets @code{inhibit-default-init}
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to a non-@code{nil} value, then Emacs does not subsequently load the
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@file{default.el} file.
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Another file for site-customization is @file{site-start.el}. Emacs
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loads this @emph{before} the user's init file. You can inhibit the
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loading of this file with the option @samp{-no-site-file}.
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loading of this file with the option @samp{--no-site-file}.
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@defvar site-run-file
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This variable specifies the site-customization file to load before the
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@ -1526,7 +1527,7 @@ uses interrupts if that is the way it knows how to communicate.
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If @var{flow} is non-@code{nil}, then Emacs uses @sc{xon/xoff}
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(@kbd{C-q}, @kbd{C-s}) flow control for output to the terminal. This
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has no effect except in @sc{cbreak} mode. @xref{Flow Control}.
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has no effect except in @sc{cbreak} mode.
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@c Emacs 19 feature
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The argument @var{meta} controls support for input character codes
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@ -1621,7 +1622,7 @@ In the example below, we set @code{keyboard-translate-table} to a
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char-table. Then we fill it in to swap the characters @kbd{C-s} and
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@kbd{C-\} and the characters @kbd{C-q} and @kbd{C-^}. Subsequently,
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typing @kbd{C-\} has all the usual effects of typing @kbd{C-s}, and vice
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versa. (@xref{Flow Control}, for more information on this subject.)
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versa.
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@cindex flow control example
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@example
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@ -1820,7 +1821,7 @@ trigger an Emacs bug, for the sake of a bug report.
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@section Terminal Output
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@cindex terminal output
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The terminal output functions send output to the terminal, or keep
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The terminal output functions send output to a text terminal, or keep
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track of output sent to the terminal. The variable @code{baud-rate}
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tells you what Emacs thinks is the output speed of the terminal.
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@ -1852,6 +1853,7 @@ This obsolete function returns the value of the variable
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@defun send-string-to-terminal string
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This function sends @var{string} to the terminal without alteration.
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Control characters in @var{string} have terminal-dependent effects.
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This function operates only on text terminals.
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One use of this function is to define function keys on terminals that
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have downloadable function key definitions. For example, this is how (on
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@ -2003,98 +2005,6 @@ how to swap the Meta and Alt modifiers within Emacs:
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@end lisp
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@end defvar
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@node Flow Control
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@section Flow Control
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@cindex flow control characters
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This section attempts to answer the question ``Why does Emacs use
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flow-control characters in its command character set?'' For a second
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view on this issue, read the comments on flow control in the
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@file{emacs/INSTALL} file from the distribution; for help with Termcap
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entries and DEC terminal concentrators, see @file{emacs/etc/TERMS}.
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@cindex @kbd{C-s}
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@cindex @kbd{C-q}
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At one time, most terminals did not need flow control, and none used
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@code{C-s} and @kbd{C-q} for flow control. Therefore, the choice of
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@kbd{C-s} and @kbd{C-q} as command characters for searching and quoting
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was natural and uncontroversial. With so many commands needing key
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assignments, of course we assigned meanings to nearly all @acronym{ASCII}
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control characters.
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Later, some terminals were introduced which required these characters
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for flow control. They were not very good terminals for full-screen
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editing, so Emacs maintainers ignored them. In later years, flow
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control with @kbd{C-s} and @kbd{C-q} became widespread among terminals,
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but by this time it was usually an option. And the majority of Emacs
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users, who can turn flow control off, did not want to switch to less
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mnemonic key bindings for the sake of flow control.
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So which usage is ``right''---Emacs's or that of some terminal and
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concentrator manufacturers? This question has no simple answer.
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One reason why we are reluctant to cater to the problems caused by
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@kbd{C-s} and @kbd{C-q} is that they are gratuitous. There are other
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techniques (albeit less common in practice) for flow control that
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preserve transparency of the character stream. Note also that their use
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for flow control is not an official standard. Interestingly, on the
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model 33 teletype with a paper tape punch (around 1970), @kbd{C-s} and
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@kbd{C-q} were sent by the computer to turn the punch on and off!
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As window systems and PC terminal emulators replace character-only
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terminals, the flow control problem is gradually disappearing. For the
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mean time, Emacs provides a convenient way of enabling flow control if
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you want it: call the function @code{enable-flow-control}.
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@deffn Command enable-flow-control &optional arg
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When @var{arg} is a positive integer, this function enables use of
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@kbd{C-s} and @kbd{C-q} for output flow control, and provides the
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characters @kbd{C-\} and @kbd{C-^} as aliases for them using
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@code{keyboard-translate-table} (@pxref{Translating Input}).
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When @var{arg} is a negative integer or zero, it disables these
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features. When @var{arg} is @code{nil} or omitted, it toggles.
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Interactively, @var{arg} is the prefix argument. If non-@code{nil},
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its numeric value is used.
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@end deffn
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You can use the function @code{enable-flow-control-on} in your
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init file to enable flow control automatically on certain
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terminal types.
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@defun enable-flow-control-on &rest termtypes
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This function enables flow control, and the aliases @kbd{C-\} and @kbd{C-^},
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if the terminal type is one of @var{termtypes}. For example:
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@smallexample
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(enable-flow-control-on "vt200" "vt300" "vt101" "vt131")
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@end smallexample
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@end defun
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Here is how @code{enable-flow-control} does its job:
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@enumerate
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@item
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@cindex @sc{cbreak}
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It sets @sc{cbreak} mode for terminal input, and tells the operating
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system to handle flow control. This is done using @code{set-input-mode}.
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@item
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It sets up @code{keyboard-translate-table} to translate @kbd{C-\} and
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@kbd{C-^} into @kbd{C-s} and @kbd{C-q}. Except at its very
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lowest level, Emacs never knows that the characters typed were anything
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but @kbd{C-s} and @kbd{C-q}, so you can in effect type them as @kbd{C-\}
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and @kbd{C-^} even when they are input for other commands.
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@xref{Translating Input}.
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@end enumerate
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If the terminal is the source of the flow control characters, then once
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you enable kernel flow control handling, you probably can make do with
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less padding than normal for that terminal. You can reduce the amount
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of padding by customizing the Termcap entry. You can also reduce it by
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setting @code{baud-rate} to a smaller value so that Emacs uses a smaller
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speed when calculating the padding needed. @xref{Terminal Output}.
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@node Batch Mode
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@section Batch Mode
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@cindex batch mode
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@ -2106,8 +2016,8 @@ terminal, it does not alter the terminal modes, and it does not expect
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to be outputting to an erasable screen. The idea is that you specify
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Lisp programs to run; when they are finished, Emacs should exit. The
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way to specify the programs to run is with @samp{-l @var{file}}, which
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loads the library named @var{file}, and @samp{-f @var{function}}, which
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calls @var{function} with no arguments.
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loads the library named @var{file}, or @samp{-f @var{function}}, which
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calls @var{function} with no arguments, or @samp{--eval @var{form}}.
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Any Lisp program output that would normally go to the echo area,
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either using @code{message}, or using @code{prin1}, etc., with @code{t}
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