3.3.2.3 Limiting Command Size

xargs gives you control over how many arguments it passes to the command each time it executes it. By default, it uses up to ARG_MAX - 2k, or 128k, whichever is smaller, characters per command. It uses as many lines and arguments as fit within that limit. The following options modify those values.

--no-run-if-empty

-r

If the standard input does not contain any nonblanks, do not run the command. By default, the command is run once even if there is no input.

--max-lines[=max-lines]

-l[max-lines]

Use at most max-lines nonblank input lines per command line; max-lines defaults to 1 if omitted. Trailing blanks cause an input line to be logically continued on the next input line, for the purpose of counting the lines. Implies -x.

--max-args=max-args

-n 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.

--max-chars=max-chars

-s 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. If you specify a value for this option which is too large or small, a warning message is printed and the appropriate upper or lower limit is used instead.

--max-procs=max-procs

-P 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, -s, or -l option with -P; otherwise chances are that the command will be run only once.