Shells

A shell is just a program which interprets and executes commands. It may be used for scripting or user interaction (login shell).

For users who spend most of their time running applications with a GUI, the choice of login shell may be immaterial. For those who use a shell as the primary means of interaction with the computer, the choice is critical.

Examples in this section assume BASH, the Bourne Again SHell. Commands appear in a monospaced font. Examples usually also show the canonical unprivileged user's prompt ($). I've indicated equivalent csh commands when I knew them.