`xargs` Build commands from standard input

Reads items from standard input and runs another command with them as arguments. Use it when a command takes file names as arguments but you have them as a list, for example the output of find.

Synopsis

xargs [OPTION]... [COMMAND [ARG]...]
find ... -print0 | xargs -0 COMMAND

Common options

Option or form	What it does
`-0, --null`	Expect input items separated by NUL characters instead of whitespace. Pair it with find -print0 so odd file names are safe
`-I replstr`	Run the command once per input line, replacing replstr (often {}) with that line wherever it appears in the command
`-n number`	Pass at most number arguments to each run of the command. -n 1 runs it once per item
`-P maxprocs`	Run up to maxprocs commands at the same time. -P 0 uses as many as possible
`-p`	Ask for confirmation before each run
`-t`	Print each command to standard error before running it
`-r, --no-run-if-empty`	Do not run the command when the input is empty. Needed on GNU/Linux, accepted but not needed on macOS
`-E eofstr`	Stop reading input when a line equals eofstr

Examples

Pass lines of input as arguments

printf 'a.txt\nb.txt\n' | xargs touch

Run the command once per item

printf '1\n2\n3\n' | xargs -n 1 echo item

item 1
item 2
item 3

Count lines in every text file found

find docs -name '*.md' -print0 | xargs -0 wc -l

Use a placeholder to put each name in the middle of a command

find photos -name '*.jpg' | xargs -I{} cp {} {}.bak

Show details for every file find lists

find docs -type f -print0 | xargs -0 ls -l

Compress many files, four at a time

find . -name '*.log' -print0 | xargs -0 -P 4 gzip

Notes

By default xargs splits on spaces, tabs and newlines, and treats quotes and backslashes specially. A file called my notes.txt becomes two arguments. Use find -print0 with xargs -0 for any file names you do not control.
With empty input, GNU xargs runs the command once with no arguments unless you add -r. macOS (BSD) xargs does not run it at all, and accepts -r only for compatibility. Add -r in scripts that must also run on Linux.
xargs may split a long list over several runs of the command, because of the system limit on argument length. Results that need all items at once, such as sort, can come out wrong.
-I{} runs the command once per line and is slower than the default. It also treats each whole line as one item, spaces included.
Check the list before running something destructive. Put echo in front of the command (xargs echo rm) to preview it.

xargs Build commands from standard input

Synopsis

Common options

Examples

Notes

See also

`xargs` Build commands from standard input