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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | EXAMPLES | EXIT STATUS | STANDARDS CONFORMANCE | HISTORY | BUGS | REPORTING BUGS | COPYRIGHT | SEE ALSO | COLOPHON |
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XARGS(1) General Commands Manual XARGS(1)
xargs - build and execute command lines from standard input
xargs [option ...] [command] [initial-argument ...]
This manual page documents the GNU version of xargs. xargs reads
items from the standard input, delimited by blanks (which can be
protected with double or single quotes or a backslash) or
newlines, and executes the command (default is echo) one or more
times with any initial-arguments followed by items read from
standard input. Blank lines on the standard input are ignored.
The command line for command is built up until it reaches a
system-defined limit (unless the -n and -L options are used). The
specified command will be invoked as many times as necessary to
use up the list of input items. In general, there will be many
fewer invocations of command than there were items in the input.
This will normally have significant performance benefits. Some
commands can usefully be executed in parallel too; see the -P
option.
Because Unix filenames can contain blanks and newlines, this
default behaviour is often problematic; filenames containing
blanks and/or newlines are incorrectly processed by xargs. In
these situations it is better to use the -0 option, which prevents
such problems. When using this option you will need to ensure
that the program which produces the input for xargs also uses a
null character as a separator. If that program is GNU find for
example, the -print0 option does this for you.
If any invocation of the command exits with a status of 255, xargs
will stop immediately without reading any further input. An error
message is issued on standard error when this happens.
-0
--null Input items are terminated by a null character instead of
by whitespace, and the quotes and backslash are not special
(every character is taken literally). Disables the end-of-
file string, which is treated like any other argument.
Useful when input items might contain white space, quote
marks, or backslashes. The GNU find (and from POSIX Issue
8, IEEE Std 1003.1-2024) -print0 option produces input
suitable for this mode.
-a file
--arg-file=file
Read items from file instead of standard input. If you use
this option, standard input remains unchanged when commands
are run. Otherwise, standard input is redirected from
/dev/null.
--delimiter=delim
-d delim
Input items are terminated by the specified character. The
specified delimiter may be a single character, a C-style
character escape such as \n, or an octal or hexadecimal
escape code. Octal and hexadecimal escape codes are
understood as for the printf command. Multibyte characters
are not supported. When processing the input, quotes and
backslash are not special; every character in the input is
taken literally. The -d option disables any end-of-file
string, which is treated like any other argument. You can
use this option when the input consists of simply newline-
separated items, although it is almost always better to
design your program to use --null where this is possible.
-E eof-str
Set the end-of-file string to eof-str. If the end-of-file
string occurs as a line of input, the rest of the input is
ignored. If neither -E nor -e is used, no end-of-file
string is used.
-e[eof-str]
--eof[=eof-str]
This option is a synonym for the -E option. Use -E
instead, because it is POSIX-compliant while this option is
not. If eof-str is omitted, there is no end-of-file
string. If neither -E nor -e is used, no end-of-file
string is used.
-I replace-str
Replace occurrences of replace-str in the initial-arguments
with names read from standard input. Also, unquoted blanks
do not terminate input items; instead the separator is the
newline character. Implies -x and “-L 1”.
-i[replace-str]
--replace[=replace-str]
This option is a synonym for -Ireplace-str if replace-str
is specified. If the replace-str argument is missing, the
effect is the same as “-I{}”. The -i option is deprecated;
use -I instead.
-L max-lines
Use at most max-lines nonblank input lines per command
line. Trailing blanks cause an input line to be logically
continued on the next input line. Implies -x.
-l[max-lines]
--max-lines[=max-lines]
Synonym for the -L option. Unlike -L, the max-lines
argument is optional. If max-lines is not specified, it
defaults to one. The -l option is deprecated since the
POSIX standard specifies -L instead.
-n max-args
--max-args=max-args
Use at most max-args arguments per command line. Fewer
than max-args arguments will be used if the size (see the
-s option) is exceeded, unless the -x option is given, in
which case xargs will exit.
-P max-procs
--max-procs=max-procs
Run up to max-procs processes at a time; the default is 1.
If max-procs is 0, xargs will run as many processes as
possible at a time. Use the -n option or the -L option
with -P; otherwise chances are that only one exec will be
done. While xargs is running, you can send its process a
SIGUSR1 signal to increase the number of commands to run
simultaneously, or a SIGUSR2 to decrease the number. You
cannot increase it above an implementation-defined limit
(which is shown with --show-limits). You cannot decrease
it below 1. xargs never terminates its commands; when
asked to decrease, it merely waits for more than one
existing command to terminate before starting another.
xargs always waits for all child processes to exit before
exiting itself (but see BUGS).
If you do not use the -P option, xargs will not handle the
SIGUSR1 and SIGUSR2 signals, meaning that they will
terminate the program (unless they were blocked in the
parent process before xargs was started).
Please note that it is up to the called processes to
properly manage parallel access to shared resources. For
example, if more than one of them tries to print to
standard output, the output will be produced in an
indeterminate order (and very likely mixed up) unless the
processes collaborate in some way to prevent this. Using
some kind of locking scheme is one way to prevent such
problems. In general, using a locking scheme will help
ensure correct output but reduce performance. If you don't
want to tolerate the performance difference, simply arrange
for each process to produce a separate output file (or
otherwise use separate resources).
-o
--open-tty
Reopen standard input as /dev/tty in the child process
before executing the command. This is useful if you want
xargs to run an interactive application.
-p
--interactive
Prompt the user about whether to run each command line and
read a line from the terminal. Only run the command line
if the response starts with `y' or `Y'. Implies -t.
--process-slot-var=name
Set the environment variable name to a unique value in each
running child process. Values are reused once child
processes exit. This can be used in a rudimentary load
distribution scheme, for example.
-r
--no-run-if-empty
If the standard input does not contain any nonblanks, do
not run the command. Normally, the command is run once
even if there is no input. This option is a GNU extension.
-s max-chars
--max-chars=max-chars
Use at most max-chars characters per command line,
including the command and initial-arguments and the
terminating nulls at the ends of the argument strings. The
largest allowed value is system-dependent, and is
calculated as the argument length limit for exec, less the
size of your environment, less 2048 bytes of headroom. If
this value is more than 128 KiB, 128 KiB is used as the
default value; otherwise, the default value is the maximum.
1 KiB is 1024 bytes. xargs automatically adapts to tighter
constraints.
--show-limits
Display the limits on the command-line length which are
imposed by the operating system, xargs' choice of buffer
size and the -s option. Pipe the input from /dev/null (and
perhaps specify --no-run-if-empty) if you don't want xargs
to do anything.
-t
--verbose
Print the command line on the standard error output before
executing it.
-x
--exit Exit if the size (see the -s option) is exceeded.
-- Delimit the option list. Later arguments, if any, are
treated as operands even if they begin with “-”. For
example, “xargs -- --help” runs the command --help (found
in PATH) instead of printing the usage text, and “xargs --
--mycommand” runs the command --mycommand instead of
rejecting this as unrecognized option.
--help Print a summary of the options to xargs and exit.
--version
Print the version number of xargs and exit.
The options --max-lines (-L, -l), --replace (-I, -i), and
--max-args (-n) are mutually exclusive. If some of them are
specified at the same time, then xargs will generally use the
option specified last on the command line, i.e., it will reset the
value of the offending option (given before) to its default value.
Additionally, xargs will issue a warning diagnostic on standard
error. The exception to this rule is that the special max-args
value “1” (as in “-n1”) is ignored after the --replace option and
its aliases -I and -i, because it would not actually conflict.
find /tmp -name core -type f -print | xargs /bin/rm -f
Find files named core in or below the directory /tmp and delete
them. Note that this will work incorrectly if there are any
filenames containing newlines or spaces.
find /tmp -name core -type f -print0 | xargs -0 /bin/rm -f
Find files named core in or below the directory /tmp and delete
them, processing filenames in such a way that file or directory
names containing spaces or newlines are correctly handled.
find /tmp -depth -name core -type f -delete
Find files named core in or below the directory /tmp and delete
them, but more efficiently than in the previous example (because
we avoid the need to use fork(2) and exec(2) to launch rm and we
don't need the extra xargs process).
cut -d: -f1 < /etc/passwd | sort | xargs echo
Generates a compact listing of all the users on the system.
xargs exits with the following status:
0 if it succeeds
123 if any invocation of the command exited with status
1–125
124 if the command exited with status 255
125 if the command is killed by a signal
126 if the command cannot be run
127 if the command is not found
1 if some other error occurred.
Exit codes greater than 128 are used by the shell to indicate that
a program died due to a fatal signal.
The long-standing -0 option of xargs appeared first in Issue 8
(IEEE Std 1003.1-2024) of the POSIX standard.
As of GNU findutils version 4.2.9, the default behaviour of xargs
is not to have a logical end-of-file marker. POSIX (IEEE Std
1003.1, 2004 Edition) allows this.
The -l and -i options appear in the 1997 version of the POSIX
standard, but do not appear in the 2004 version of the standard.
Therefore you should use -L and -I instead, respectively.
The -o option is an extension to the POSIX standard for better
compatibility with BSD.
The POSIX standard allows implementations to have a limit on the
size of arguments to the exec functions. This limit could be as
low as 4096 bytes including the size of the environment. For
scripts to be portable, they must not rely on a larger value.
However, I know of no implementation whose actual limit is that
small. The --show-limits option can be used to discover the
actual limits in force on the current system.
In versions of xargs up to and including version 4.9.0, SIGUSR1
and SIGUSR2 would not cause xargs to terminate even if the -P
option was not used.
The xargs program was invented by Herb Gellis at Bell Labs. See
the Texinfo manual for findutils, chapter “Finding Files”, for
more information.
It is not possible for xargs to be used securely, since there will
always be a time gap between the production of the list of input
files and their use in the commands that xargs issues. If other
users have access to the system, they can manipulate the
filesystem during this time window to force the action of the
commands xargs runs to apply to files that you didn't intend. For
a more detailed discussion of this and related problems, please
refer to the “Security Considerations” chapter in the findutils
Texinfo documentation. The -execdir option of find can often be
used as a more secure alternative.
When you use the -I option, each line read from the input is
buffered internally. This means that there is an upper limit on
the length of input line that xargs will accept when used with the
-I option. To work around this limitation, you can use the -s
option to increase the amount of buffer space that xargs uses, and
you can also use an extra invocation of xargs to ensure that very
long lines do not occur. For example:
somecommand | xargs -s 50000 echo | xargs -I '{}' -s 100000 rm
'{}'
Here, the first invocation of xargs has no input line length limit
because it doesn't use the -i option. The second invocation of
xargs does have such a limit, but we have ensured that it never
encounters a line which is longer than it can handle. This is not
an ideal solution. Instead, the -i option should not impose a
line length limit, which is why this discussion appears in the
BUGS section. The problem doesn't occur with the output of
find(1) because it emits just one filename per line.
In versions of xargs up to and including version 4.9.0, xargs -P
would exit while some of its children were still running, if one
of them exited with status 255.
GNU findutils online help:
<https://www.gnu.org/software/findutils/#get-help>
Report any translation bugs to
<https://translationproject.org/team/>
Report any other issue via the form at the GNU Savannah bug
tracker:
<https://savannah.gnu.org/bugs/?group=findutils>
General topics about the GNU findutils package are discussed at
the bug-findutils mailing list:
<https://lists.gnu.org/mailman/listinfo/bug-findutils>
Copyright © 1990–2026 Free Software Foundation, Inc. License
GPLv3+: GNU GPL version 3 or later
<https://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
find(1), kill(1), locate(1), updatedb(1), fork(2), execvp(3),
locatedb(5), signal(7)
Full documentation <https://www.gnu.org/software/findutils/xargs>
or available locally via: info xargs
This page is part of the findutils (find utilities) project.
Information about the project can be found at
⟨http://www.gnu.org/software/findutils/⟩. If you have a bug report
for this manual page, see
⟨https://savannah.gnu.org/bugs/?group=findutils⟩. This page was
obtained from the project's upstream Git repository
⟨git://git.savannah.gnu.org/findutils.git⟩ on 2026-01-16. (At
that time, the date of the most recent commit that was found in
the repository was 2026-01-06.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
findutils 2024-06-03 XARGS(1)
Pages that refer to this page: dpkg-name(1), find(1), grep(1), locate(1), updatedb(1), lsof(8)
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HTML rendering created 2026-01-16 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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