Perl’s for control structure is like the common for control structure you may have seen in other languages such as C. It looks like this:

for (initialization; test; increment) {
    body;
    body;
}

To Perl, though, this kind of loop is really a while loop in disguise, something like this:^[266]

initialization;
while (test) {
    body;
    body;
    increment;
}

The most common use of the for loop, by far, is for making computed iterations:

for ($i = 1; $i <= 10; $i++) {  # count from 1 to 10
    print "I can count to $i!\n";
}

When you’ve seen these before, you’ll know what the first line is saying even before you read the comment. Before the loop starts, the control variable, $i, is set to 1. Then, the loop is really a while loop in disguise, looping while $i is less than or equal to 10. Between each iteration and the next is the increment, which here is a literal increment, adding one to the control variable, which is $i.