We have actually met most of the shell built-ins already. You may be wondering what a shell built-in is; these are commands that are built into the actual Bourne shell instead of residing in the /bin or usr/bin directory. Built-in commands run faster than their equivalent (if any) in the system.
In this chapter we will cover:
the list of the standard Bourne shell built-in commands.
For instance, we have used cd and pwd, which can be found both in the system and as a shell built-in. To run the system version simply supply the path to the command: