Ubuntu Unleashed 2013 Edition: Covering 12.10 and 13.04, Eighth Edition

The break and exit Statements

You should be aware of two other statements: the break statement and the exit statement.

You can use the break statement used to terminate an iteration loop, such as a for, until, or repeat command.

You can use exit statements to exit a shell program. You can optionally use a number after exit. If the current shell program has been called by another shell program, the calling program can check for the code (the $? or $status variable, depending on shell) and make a decision accordingly.