zsh

autocompletion: If not set up correctly run the script:

source /usr/share/zsh/4.0.6/functions/Completion/compinstall

or something similar (compinstall could be in a different place)

the script will edit your .zshrc file for you with the settings you choose.

references:

http://nothing.tmtm.com/2003/01/zsh-tab-completion/