Linux Shells by Example

11.7. Loops

Looping constructs allow you to execute the same statements a number of times. The C shell supports two types of loops: the foreach loop and the while loop. The foreach loop is used when you need to execute commands on a list of items, one item at a time, such as a list of files or a list of usernames. The while loop is used when you want to keep executing a command until a certain condition is met.

11.7.1. The foreach Loop

The foreach command is followed by a variable and a wordlist enclosed in parentheses. The first time the loop is entered, the first word in the list is assigned to the variable. The list is shifted to the left by one and the body of the loop is entered. Each command in the loop body is executed until the end ...