Summary

In this chapter, we discussed how repetitive commands can be incorporated in loop constructs. Most common loops are built using the for, while or until statements, or a combination of these commands. The for loop executes a task a defined number of times. If you don't know how many times a command should execute, use either until or while to specify when the loop should end.

Loops can be interrupted or reiterated using the break and continue statements.

A file can be used as input for a loop using the input redirection operator, loops can also read output from commands that is fed into the loop using a pipe.

The select construct is used for printing menus in interactive scripts. Looping through the command line arguments to a script can be done using the shift statement.