Sams Teach Yourself Shell Programming in 24 Hours, Second Edition

The for and select Loops

Unlike the while loop, which exits when a certain condition is false, the for and select loops operate on lists of items. This section covers these two loops in detail.

The for Loop

The for loop enables you to execute a set of commands repeatedly for each item in a list. One of its most common uses is in performing the same set of commands for a large number of files. The basic syntax is

for name in word1 word2 ... wordN
do list done

Here name is the name of a variable and word1 to wordN are sequences of characters separated by spaces (words). Each time the for loop executes, the value of the variable name is set to the next word in the list of words, word1 to wordN. The first time, name is set to word1; the second ...