zsh

Completion

Zsh uses widgets to provide completions. Define a completion widget named 'complete':

zle -C complete expand-or-complete completer

The second argument to the zle command is the name of any of the builtin widgets that handle completions:

The third argument is the name of the function that will provide completions.

Enable a completion widget:

zstyle ':completion:*' use-cache on
zstyle ':completion:*' cache-path ~/.zsh/cache

The first argument to zstyle is called a context and is defined as follows:

:completion:<function-name>:<completer>:<command>:<argument>:<tag>

Where

function-name
completer - name of the currently active completer function
command - name of the current command for which completion is performed, e.g. git-add
argument - name of the command line or option argument being completed
tag

zstyle ':completion:' matcher-list 'm:{a-zA-Z}={A-Za-z}' '+r:|[._-]=* r:|=**'

matcher-list is set to a list of match specifications. completion system will try them one after another for each completer selected.

_complete completer

Command line and trial completion patterns are anchored on the left side:

l:lanchor|lpat=tpat

On the right side:

r:lpat|ranchor=tpat