zsh change directory (cd) dot expansion

Extracted from the prezto editor module.

Expands

cd ...

to

cd ../..

and so forth in zsh.

Use this in combination with the

setopt auto_cd

zsh option and you can omit the cd and just type ... to change to the second directory above.

Install with Antigen

antigen bundle wazum/zsh-directory-dot-expansion

Install with zplug

zplug "wazum/zsh-directory-dot-expansion"

oh-my-zsh

oh-my-zsh does something similar with aliases, see https://github.com/robbyrussell/oh-my-zsh/blob/master/lib/directories.zsh