Zsh

zsh (Z shell) is an interactive login shell that can also be used as a powerful scripting language interpreter. It is similar to bash and the Korn shell, but offers extensive configurability, powerful command-line completion, file globbing, and spelling correction.

Emerge
Install :

app-shells/zsh-completion
Emerging enables auto-completion for arguments of commands, which is one of the advantages zsh has over other shells:

app-shells/gentoo-zsh-completions
Emerging enables Gentoo specific auto-completion for arguments of Portage and other Gentoo commands:

When installing this package be sure to add the following to the respective files:

To enable a cache for the completions add:

Invocation
Upon running zsh for the first time as a new user, you will be greeted by a basic configuration dialog. The setup process can be skipped by pressing. If the setup process is skipped zsh can be setup manually.

Setting zsh as the default shell
To make zsh the default shell for a user, run:

File
zsh's main configuration file is located in each user's home directory at. Reload this file in running shells for the changes to take effect:

External resources

 * Official zsh introduction
 * Official User's Guide
 * zsh</tt> Documentation in various formats
 * zsh</tt> FAQ
 * zsh</tt> Wiki
 * zsh</tt> Lovers
 * GRML zsh</tt> Configuration
 * oh-my-zsh
 * Sorin Ionescu maintained oh-my-zsh fork now called prezto - The configuration framework for zsh</tt>
 * ArchWiki zsh</tt> page