Moving beyond basic Bash
Even beginners can benefit from a greater understanding of the Bash shell’s many builtin commands.
Most GNU/ Linux users know that the command line uses Bash (Bourne Again Shell), but what fewer know is that, by default, they use the plainest version of Bash. The truth is that Bash is a command much like any other. It might be the command that runs other commands – a command interpreter – but, just like any other command, its behavior can be radically altered by the options you add when starting it up or by running some of its built-in commands (builtins). Moreover, you can even choose an entirely different shell through which to interact with your system.