mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-22 11:17:19 +00:00
338 lines
8.5 KiB
Groff
338 lines
8.5 KiB
Groff
.\" Copyright (c) 1990, 1991, 1993
|
|
.\" The Regents of the University of California. All rights reserved.
|
|
.\"
|
|
.\" This code is derived from software contributed to Berkeley by
|
|
.\" John B. Roll Jr. and the Institute of Electrical and Electronics
|
|
.\" Engineers, Inc.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 3. All advertising materials mentioning features or use of this software
|
|
.\" must display the following acknowledgement:
|
|
.\" This product includes software developed by the University of
|
|
.\" California, Berkeley and its contributors.
|
|
.\" 4. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" @(#)xargs.1 8.1 (Berkeley) 6/6/93
|
|
.\" $FreeBSD$
|
|
.\" $xMach: xargs.1,v 1.2 2002/02/23 05:23:37 tim Exp $
|
|
.\"
|
|
.Dd December 30, 2005
|
|
.Dt XARGS 1
|
|
.Os
|
|
.Sh NAME
|
|
.Nm xargs
|
|
.Nd "construct argument list(s) and execute utility"
|
|
.Sh SYNOPSIS
|
|
.Nm
|
|
.Op Fl 0opt
|
|
.Op Fl E Ar eofstr
|
|
.Oo
|
|
.Fl I Ar replstr
|
|
.Op Fl R Ar replacements
|
|
.Op Fl S Ar replsize
|
|
.Oc
|
|
.Op Fl J Ar replstr
|
|
.Op Fl L Ar number
|
|
.Oo
|
|
.Fl n Ar number
|
|
.Op Fl x
|
|
.Oc
|
|
.Op Fl P Ar maxprocs
|
|
.Op Fl s Ar size
|
|
.Op Ar utility Op Ar argument ...
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Nm
|
|
utility reads space, tab, newline and end-of-file delimited strings
|
|
from the standard input and executes
|
|
.Ar utility
|
|
with the strings as
|
|
arguments.
|
|
.Pp
|
|
Any arguments specified on the command line are given to
|
|
.Ar utility
|
|
upon each invocation, followed by some number of the arguments read
|
|
from the standard input of
|
|
.Nm .
|
|
This is repeated until standard input is exhausted.
|
|
.Pp
|
|
Spaces, tabs and newlines may be embedded in arguments using single
|
|
(``\ '\ '')
|
|
or double (``"'') quotes or backslashes (``\e'').
|
|
Single quotes escape all non-single quote characters, excluding newlines,
|
|
up to the matching single quote.
|
|
Double quotes escape all non-double quote characters, excluding newlines,
|
|
up to the matching double quote.
|
|
Any single character, including newlines, may be escaped by a backslash.
|
|
.Pp
|
|
The options are as follows:
|
|
.Bl -tag -width indent
|
|
.It Fl 0
|
|
Change
|
|
.Nm
|
|
to expect NUL
|
|
(``\\0'')
|
|
characters as separators, instead of spaces and newlines.
|
|
This is expected to be used in concert with the
|
|
.Fl print0
|
|
function in
|
|
.Xr find 1 .
|
|
.It Fl E Ar eofstr
|
|
Use
|
|
.Ar eofstr
|
|
as a logical EOF marker.
|
|
.It Fl I Ar replstr
|
|
Execute
|
|
.Ar utility
|
|
for each input line, replacing one or more occurrences of
|
|
.Ar replstr
|
|
in up to
|
|
.Ar replacements
|
|
(or 5 if no
|
|
.Fl R
|
|
flag is specified) arguments to
|
|
.Ar utility
|
|
with the entire line of input.
|
|
The resulting arguments, after replacement is done, will not be allowed to grow
|
|
beyond
|
|
.Ar replsize
|
|
(or 255 if no
|
|
.Fl S
|
|
flag is specified)
|
|
bytes; this is implemented by concatenating as much of the argument
|
|
containing
|
|
.Ar replstr
|
|
as possible, to the constructed arguments to
|
|
.Ar utility ,
|
|
up to
|
|
.Ar replsize
|
|
bytes.
|
|
The size limit does not apply to arguments to
|
|
.Ar utility
|
|
which do not contain
|
|
.Ar replstr ,
|
|
and furthermore, no replacement will be done on
|
|
.Ar utility
|
|
itself.
|
|
Implies
|
|
.Fl x .
|
|
.It Fl J Ar replstr
|
|
If this option is specified,
|
|
.Nm
|
|
will use the data read from standard input to replace the first occurrence of
|
|
.Ar replstr
|
|
instead of appending that data after all other arguments.
|
|
This option will not affect how many arguments will be read from input
|
|
.Pq Fl n ,
|
|
or the size of the command(s)
|
|
.Nm
|
|
will generate
|
|
.Pq Fl s .
|
|
The option just moves where those arguments will be placed in the command(s)
|
|
that are executed.
|
|
The
|
|
.Ar replstr
|
|
must show up as a distinct
|
|
.Ar argument
|
|
to
|
|
.Nm .
|
|
It will not be recognized if, for instance, it is in the middle of a
|
|
quoted string.
|
|
Furthermore, only the first occurrence of the
|
|
.Ar replstr
|
|
will be replaced.
|
|
For example, the following command will copy the list of files and
|
|
directories which start with an uppercase letter in the current
|
|
directory to
|
|
.Pa destdir :
|
|
.Pp
|
|
.Dl /bin/ls -1d [A-Z]* | xargs -J % cp -rp % destdir
|
|
.Pp
|
|
.It Fl L Ar number
|
|
Call
|
|
.Ar utility
|
|
for every
|
|
.Ar number
|
|
lines read.
|
|
If EOF is reached and fewer lines have been read than
|
|
.Ar number
|
|
then
|
|
.Ar utility
|
|
will be called with the available lines.
|
|
.It Fl n Ar number
|
|
Set the maximum number of arguments taken from standard input for each
|
|
invocation of
|
|
.Ar utility .
|
|
An invocation of
|
|
.Ar utility
|
|
will use less than
|
|
.Ar number
|
|
standard input arguments if the number of bytes accumulated (see the
|
|
.Fl s
|
|
option) exceeds the specified
|
|
.Ar size
|
|
or there are fewer than
|
|
.Ar number
|
|
arguments remaining for the last invocation of
|
|
.Ar utility .
|
|
The current default value for
|
|
.Ar number
|
|
is 5000.
|
|
.It Fl o
|
|
Reopen stdin as
|
|
.Pa /dev/tty
|
|
in the child process before executing the command.
|
|
This is useful if you want
|
|
.Nm
|
|
to run an interactive application.
|
|
.It Fl P Ar maxprocs
|
|
Parallel mode: run at most
|
|
.Ar maxprocs
|
|
invocations of
|
|
.Ar utility
|
|
at once.
|
|
.It Fl p
|
|
Echo each command to be executed and ask the user whether it should be
|
|
executed.
|
|
An affirmative response,
|
|
.Ql y
|
|
in the POSIX locale,
|
|
causes the command to be executed, any other response causes it to be
|
|
skipped.
|
|
No commands are executed if the process is not attached to a terminal.
|
|
.It Fl R Ar replacements
|
|
Specify the maximum number of arguments that
|
|
.Fl I
|
|
will do replacement in.
|
|
If
|
|
.Ar replacements
|
|
is negative, the number of arguments in which to replace is unbounded.
|
|
.It Fl S Ar replsize
|
|
Specify the amount of space (in bytes) that
|
|
.Fl I
|
|
can use for replacements.
|
|
The default for
|
|
.Ar replsize
|
|
is 255.
|
|
.It Fl s Ar size
|
|
Set the maximum number of bytes for the command line length provided to
|
|
.Ar utility .
|
|
The sum of the length of the utility name, the arguments passed to
|
|
.Ar utility
|
|
(including
|
|
.Dv NULL
|
|
terminators) and the current environment will be less than or equal to
|
|
this number.
|
|
The current default value for
|
|
.Ar size
|
|
is
|
|
.Dv ARG_MAX
|
|
- 4096.
|
|
.It Fl t
|
|
Echo the command to be executed to standard error immediately before it
|
|
is executed.
|
|
.It Fl x
|
|
Force
|
|
.Nm
|
|
to terminate immediately if a command line containing
|
|
.Ar number
|
|
arguments will not fit in the specified (or default) command line length.
|
|
.El
|
|
.Pp
|
|
If
|
|
.Ar utility
|
|
is omitted,
|
|
.Xr echo 1
|
|
is used.
|
|
.Pp
|
|
Undefined behavior may occur if
|
|
.Ar utility
|
|
reads from the standard input.
|
|
.Pp
|
|
The
|
|
.Nm
|
|
utility exits immediately (without processing any further input) if a
|
|
command line cannot be assembled,
|
|
.Ar utility
|
|
cannot be invoked, an invocation of
|
|
.Ar utility
|
|
is terminated by a signal,
|
|
or an invocation of
|
|
.Ar utility
|
|
exits with a value of 255.
|
|
.Sh EXIT STATUS
|
|
The
|
|
.Nm
|
|
utility exits with a value of 0 if no error occurs.
|
|
If
|
|
.Ar utility
|
|
cannot be found,
|
|
.Nm
|
|
exits with a value of 127, otherwise if
|
|
.Ar utility
|
|
cannot be executed,
|
|
.Nm
|
|
exits with a value of 126.
|
|
If any other error occurs,
|
|
.Nm
|
|
exits with a value of 1.
|
|
.Sh SEE ALSO
|
|
.Xr echo 1 ,
|
|
.Xr find 1 ,
|
|
.Xr execvp 3
|
|
.Sh STANDARDS
|
|
The
|
|
.Nm
|
|
utility is expected to be
|
|
.St -p1003.2
|
|
compliant.
|
|
The
|
|
.Fl J , o , P, R
|
|
and
|
|
.Fl S
|
|
options are non-standard
|
|
.Fx
|
|
extensions which may not be available on other operating systems.
|
|
.Sh HISTORY
|
|
The
|
|
.Nm
|
|
utility appeared in PWB UNIX.
|
|
.Sh BUGS
|
|
If
|
|
.Ar utility
|
|
attempts to invoke another command such that the number of arguments or the
|
|
size of the environment is increased, it risks
|
|
.Xr execvp 3
|
|
failing with
|
|
.Er E2BIG .
|
|
.Pp
|
|
The
|
|
.Nm
|
|
utility does not take multibyte characters into account when performing
|
|
string comparisons for the
|
|
.Fl I
|
|
and
|
|
.Fl J
|
|
options, which may lead to incorrect results in some locales.
|