Linux "xargs" Command Line Options and Examples
build and execute command lines from standard input

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 com‐ mand (default is /bin/echo) one or more times with any initial-arguments followed by items read from standard input.


Usage:

xargs [options] [command [initial-arguments]]






Command Line Options:

-0
Input items are terminated by a null character instead of by whitespace, and the quotes and backslashare not special (every character is taken literally). Disables the end of file string, which is treat‐ed like any other argument. Useful when input items might contain white space, quote marks, or back‐slashes. The GNU find -print0 option produces input suitable for this mode.
xargs -0 ...
-a
Read items from file instead of standard input. If you use this option, stdin remains unchanged whencommands are run. Otherwise, stdin is redirected from /dev/null.
xargs -a ...
--delimiter
Input items are terminated by the specified character. The specified delimiter may be a single charac‐ter, a C-style character escape such as \n, or an octal or hexadecimal escape code. Octal and hexadec‐imal 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 takenliterally. 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 al‐most always better to design your program to use --null where this is possible.
xargs --delimiter ...
-E
Set the end of file string to eof-str. If the end of file string occurs as a line of input, the restof the input is ignored. If neither -E nor -e is used, no end of file string is used.
xargs -E ...
-e[eof-str]
This option is a synonym for the -E option. Use -E instead, because it is POSIX compliant while thisoption 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.
xargs -e[eof-str] ...
-I
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
xargs -I ...
-i[replace-str]
This option is a synonym for -Ireplace-str if replace-str is specified. If the replace-str argument ismissing, the effect is the same as -I{}. This option is deprecated; use -I instead.
xargs -i[replace-str] ...
-L
Use at most max-lines nonblank input lines per command line. Trailing blanks cause an input line to belogically continued on the next input line. Implies -x.
xargs -L ...
-l[max-lines]
Synonym for the -L option. Unlike -L, the max-lines argument is optional. If max-lines is not speci‐fied, it defaults to one. The -l option is deprecated since the POSIX standard specifies -L instead.
xargs -l[max-lines] ...
-n
Use at most max-args arguments per command line. Fewer than max-args arguments will be used if thesize (see the -s option) is exceeded, unless the -x option is given, in which case xargs will exit.
xargs -n ...
-P
Run up to max-procs processes at a time; the default is 1. If max-procs is 0, xargs will run as manyprocesses as possible at a time. Use the -n option or the -L option with -P; otherwise chances arethat only one exec will be done. While xargs is running, you can send its process a SIGUSR1 signal toincrease the number of commands to run simultaneously, or a SIGUSR2 to decrease the number. You cannotincrease it above an implementation-defined limit (which is shown with --show-limits). You cannot de‐crease it below 1. xargs never terminates its commands; when asked to decrease, it merely waits formore than one existing command to terminate before starting another.Please note that it is up to the called processes to properly manage parallel access to shared re‐sources. For example, if more than one of them tries to print to stdout, the output will be producedin an indeterminate order (and very likely mixed up) unless the processes collaborate in some way toprevent this. Using some kind of locking scheme is one way to prevent such problems. In general, us‐ing a locking scheme will help ensure correct output but reduce performance. If you don't want to tol‐erate the performance difference, simply arrange for each process to produce a separate output file (orotherwise use separate resources).
xargs -P ...
-o
Reopen stdin as /dev/tty in the child process before executing the command. This is useful if you wantxargs to run an interactive application.
xargs -o ...
-p
Prompt the user about whether to run each command line and read a line from the terminal. Only run thecommand line if the response starts with `y' or `Y'. Implies -t.
xargs -p ...
--process-slot-var
Set the environment variable name to a unique value in each running child process. Values are reusedonce child processes exit. This can be used in a rudimentary load distribution scheme, for example.
xargs --process-slot-var ...
-r
If the standard input does not contain any nonblanks, do not run the command. Normally, the command isrun once even if there is no input. This option is a GNU extension.
xargs -r ...
-s
Use at most max-chars characters per command line, including the command and initial-arguments and theterminating 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 2048bytes of headroom. If this value is more than 128KiB, 128Kib is used as the default value; otherwise,the default value is the maximum. 1KiB is 1024 bytes. xargs automatically adapts to tighter con‐straints.
xargs -s ...
--show-limits
Display the limits on the command-line length which are imposed by the operating system, xargs' choiceof buffer size and the -s option. Pipe the input from /dev/null (and perhaps specify --no-run-if-emp‐ty) if you don't want xargs to do anything.
xargs --show-limits ...
-t
Print the command line on the standard error output before executing it.
xargs -t ...
-x
Exit if the size (see the -s option) is exceeded.
xargs -x ...
--help
Print a summary of the options to xargs and exit.
xargs --help ...
--version
Print the version number of xargs and exit.EXAMPLESfind /tmp -name core -type f -print | xargs /bin/rm -fFind files named core in or below the directory /tmp and delete them. Note that this will work incorrectly ifthere are any filenames containing newlines or spaces.find /tmp -name core -type f -print0 | xargs -0 /bin/rm -fFind files named core in or below the directory /tmp and delete them, processing filenames in such a way thatfile or directory names containing spaces or newlines are correctly handled.find /tmp -depth -name core -type f -deleteFind files named core in or below the directory /tmp and delete them, but more efficiently than in the previ‐ous example (because we avoid the need to use fork(2) and exec(2) to launch rm and we don't need the extraxargs process).cut -d: -f1 < /etc/passwd | sort | xargs echoGenerates a compact listing of all the users on the system.EXIT STATUSxargs exits with the following status:0 if it succeeds123 if any invocation of the command exited with status 1-125124 if the command exited with status 255125 if the command is killed by a signal126 if the command cannot be run127 if the command is not found1 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.STANDARDS CONFORMANCEAs of GNU xargs 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 versionof 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.
xargs --version ...