xargs

xargs [options] [command]

Execute command (with any initial arguments), but read remaining arguments from standard input instead of specifying them directly. xargs passes these arguments in several bundles to command, allowing command to process more arguments than it could normally handle at once. The arguments are typically a long list of filenames (generated by ls or find, for example) that get passed to xargs via a pipe.

Options
-0, --null	Expect filenames to be terminated by NULL instead of whitespace. Do not treat quotes or backslashes specially.
--e[string] , -E [string] , --eof[=string]	Set EOF to _ or, if specified, to string.
--help	Print a summary of the options to xargs and then exit.
-i[string] , -I [string] , --replace[=string]	Replace all occurrences of { }, or string, with the names read from standard input. Unquoted blanks are not considered argument terminators. Implies -x and -L 1.
-l[lines] , -L [lines] , --max-lines[=lines]	Allow no more than lines nonblank input lines on the command line (default is 1). Implies -x.
-n args, --max-args=args	Allow no more than args arguments on the command line. Overridden by the maximum number of characters set with -s.
-p, --interactive	Prompt for confirmation before running each command line. Implies -t.
-P max, --max-procs=max	Allow no more than max processes to run at once. The default is 1. A maximum of 0 allows as many as possible to run at once.
-r, --no-run-if-empty	Do not run command if standard input contains only blanks.
-s max, --max-chars=max	Allow no more than max characters per command line.
-t, --verbose	Verbose mode. Print command line on standard error before executing.
-x, --exit	If the maximum size (as specified by -s) is exceeded, exit.
--version	Print the version number of xargs and then exit.

Examples
grep for pattern in all files on the system:

find / | xargs grep pattern > out &
Run diff on file pairs (e.g., f1.a and f1.b, f2.a and f2.b, etc.):

echo $* | xargs -n2 diff
The previous line would be invoked as a shell script, specifying filenames as arguments. Display file, one word per line (same as deroff -w):

cat file | xargs -n1
Move files in olddir to newdir, showing each command:

ls olddir | xargs -i -t mv olddir/{ } newdir/{ }