> For the complete documentation index, see [llms.txt](https://blog.syselement.com/tcm/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://blog.syselement.com/tcm/courses/linux-101/6-shells.md).

# 6. Shells

### Topics

* Command line different shells
* Variables and files
* Redirection and command history

### Sections

1. [Common Command Line Shells](/tcm/courses/linux-101/6-shells/shells.md)
2. [Environment Variables & Startup Files](/tcm/courses/linux-101/6-shells/env-vars-files.md)
3. [Input/Output Redirection](/tcm/courses/linux-101/6-shells/io-redir.md)
4. [Command History & Substitution](/tcm/courses/linux-101/6-shells/history-sub.md)