I'm having a lot of fun taking these inscrutable lines of shell and asking AI to decipher it. Check it out:
spoiler
The ZDOTDIR variable in Zsh specifies the directory where the configuration files (.zshrc, .zshenv, .zshlogin, .zshlogout, .zprofile, and .zlogin) are located. By default, this directory is the home directory of the current user. If ZDOTDIR is set, Zsh will use the configuration files from that directory instead of the home directory.
The script you've posted appears to be setting the ZDOTDIR variable in a complex way, using Zsh parameter expansion and modifiers. Here's the breakdown:
${(%):-%x}
: This is using Zsh's %(x,y,z) prompt sequence expansion. This construct is used to insert conditional strings in the prompt. However, in this case, the construct is being abused to get the full path of the currently running script (%x), since the else branch (- modifier) of a prompt sequence expansion is always executed.
:P
: This is a Zsh parameter expansion modifier that makes the resulting path absolute by resolving symbolic links. It effectively "canonicalizes" the path.
:h
: Another Zsh parameter expansion modifier, which removes the trailing component from a path, effectively getting the directory portion of a file path. This is equivalent to dirname in a POSIX shell.
In summary, this script sets ZDOTDIR to the directory of the currently running script, resolving any symbolic links to get the absolute path. This would make Zsh look in that directory for its configuration files, instead of the home directory. It seems to be useful for a script that's bundled with its own Zsh configuration files, and wants to use those instead of the user's configuration
curious to see if AI can decipher? Certainly! bonus that we get so see potentially beneficial shell