February 2004
Beginner
200 pages
5h 40m
English
When you run a command, it might invoke a Linux program (like who), or instead it might be a built-in command, a feature of the shell itself. You can tell the difference with the type command:
$ type who who is /usr/bin/who $ type cd cd is a shell builtin
It is helpful to know what the shell provides versus what Linux does. The next few sections describe features of the shell.