xargs is great.

But why?

You should care about xargs if you believe what I write about command line tools in general, because xargs turns all of those tools into n-dimensional swiss army knives.

Briefly: xargs takes a command that you want to run as its argument and reads the inputs (arguments) to that command from STDIN.

It’s remarkably powerful when combined with any other tool that writes in a predictable way to stdout.

Here are some invocations that I like:

• The find-and-replace that you’d do in your editor, but on the command-line (and naturally, with the same flexibility): git grep --ignore-case --files-with-matches searchterm | xargs -L 1 sed -i '' 's/searchTerm/replacementTerm/g'¹
• Find lines of code for files in a directory and sort files by lines: find . | xargs wc -l | sort -nr (combine with awk to get sum of lines of code)
• This one is really great: simply use xargs -p to verify the command before each invocation. (It’s often nice to see what you’re doing before you’ve done it, especially if the operation could be risky).
• Rename all of your .js files to .ts files, with a prompt for sanity checking: find . -iname '*.js' | grep -E -i --invert-match 'node_modules|bundle' | xargs -L 1 rename 's/\.js$/\.ts/'