system environment/shells
- bash - The GNU Bourne Again shell
- bash-completion - Programmable completion for Bash
- dash - Small and fast POSIX-compliant shell
- ksh - The Original ATT Korn Shell
- mc - User-friendly text console file manager and visual shell
- tcsh - An enhanced version of csh, the C shell
- zsh - Powerful interactive shell
- zsh-html - Zsh shell manual in html format