For Statement: The First Form of For

For statement

There is another loop statement in Bash called **for**. We should use for when we know the number of iterations we need in advance.

The for statement has two forms. The first one processes words in a string sequentially. The second form applies an arithmetic expression in the loop condition.

The first form of for

Let’s start with the first form of the for statement. It looks like this in the general form:

for VARIABLE in STRING
do
  ACTION
done

We can write the same construction in a single line like this:

for VARIABLE in STRING; do ACTION; done

The ACTION of the for statement is a single command or a block of commands. It is the same thing as the one in the while statement.

Bash performs all expansions in the for condition before starting the first iteration of the loop. What does it mean? Let’s suppose we specified the command instead of the STRING. Then, Bash executes this command and replaces it with its ...