xargs run a command for each input line
xargs reads items from standard input and runs a command with those items as arguments. It connects tools that print lists (find, grep -l, sqx -o raw) to tools that take arguments, and can run several commands in parallel.
Availability Preinstalled on macOS, Linux and BSD
Syntax
xargs [options] command [initial-arguments]Common options
| Option | What it does |
|---|---|
-n N | Use at most N items per command |
-I {} | Replace {} in the command with each item, running once per item |
-P N | Run up to N commands at the same time |
-0 | Items are separated by NUL characters (pair with find -print0) |
-t | Print each command before running it |
Examples
Delete files found by find, safely
find . -name '*.tmp' -print0 | xargs -0 rmFetch headers for each URL, 4 at a time
xargs -n 1 -P 4 curl -sI < urls.txtUse xargs with sqx
Run a command for every result row
-o raw prints bare values, one per line, ready for xargs.
sqx -f users=users.csv -o raw "SELECT email FROM users WHERE plan = 'enterprise'" | xargs -n 1 echo notify:Import every CSV file into one database
sqx import appends to the table and adds new columns when files differ.
find exports -name '*.csv' | xargs -I {} sqx import -db exports.db -t rows {}File names with spaces break plain xargs. Use find -print0 with xargs -0, or -I {} with one item per line.
Full documentation
This page covers the essentials. For every option, see the official documentation:
Or read the manual in your terminal: man xargs