Zsh

ZSH is a shell, it is almost entirely backwards compatible with bash with several additional options.

Documentation

official docs	http://zsh.sourceforge.net/Doc/Release/index-frame.html
zsh manpages	https://manpages.debian.org/buster/zsh-common/index.html

Locations

~/.zshrc	rcfile
/usr/share/zsh/functions/Completion/*/*	builtin completions (see $fpath)
/usr/share/zsh/site-functions	third party zsh completions

Notes

zsh antigen

zsh plugins

zsh autocompletion