Setup

We’re going to use zsh as it is always available on any system I use:

#! /bin/zsh -f

Note

The -f option protects us from adverse interactions in the user’s zsh configuration files. They shouldn’t cause problems, but this build is part of an installation process that occurs before zsh configuration is necessarily complete.

We’ll want stricter defaults out of the box:

Option	Description
err_exit	Exit immediately if a command exits with a non-zero status.
no_unset	Treat unset variables as an error.
warn_create_global	Warn when a global variable is created.

setopt err_exit no_unset warn_create_global

We’ll need zutil to allow us to process command line arguments:

zmodload -F zsh/zutil +b:zparseopts