Today I Learned

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Using zsh functions with xargs

I want to call a zsh function with xargs, but the arguments passed to xargs don’t run in your environment.

$ function hi() { echo "hello world $@" }
$ hi person!
hello world person!
$ seq 3 | xargs hi
xargs: hi: No such file or directory

No such file or directory!? hi is a function, but xargs doesn’t see it. With a combination of environment variables, function output and zsh command execution, we can use that function with xargs.

First let’s read the definition of our function into an environment variable.

$ FUNCS=$(functions hi); echo $FUNCS
hi () {
  echo "hello world $@"

Now we can use that in combination with zsh -c to execute the function with xargs.

$ FUNCS=$(functions hi); seq 3 | xargs -I{} zsh -c "eval $FUNCS; hi {}"
hello world 1
hello world 2
hello world 3

This solution is messy but workable.