while (CONDITION) { BLOCK }

##</code><code>##

    STATEMENT while CONDITION;

##</code><code>##

    while (my $line = <FILE>) {
        # Do something with the $line
    }

##</code><code>##

    while (defined(my $line = <FILE>)) {
        # Do something with the $line
    }

##</code><code>##

$ perl -MO=Deparse -e 'while(my $line=<FILE>) { print; }'
while (defined(my $line = <FILE>)) {
    print $_;
}
-e syntax OK

##</code><code>##

    while (my $module = glob("*.pm")) {
        print "Found a module: $module\n";
    }

##</code><code>##

    my $ok=0;
    $ok=1 while my $zero = glob("0");
    print $ok ? "ok\n" : "not ok\n"

##</code><code>##

    $foo = $bar || $baz

##</code><code>##

    my $x = 1;
    die("Oh dear!") while my $foo = $x && 0;

##</code><code>##

    my $x = 1;
    die("Oh dear!") while defined(my $foo = $x && 0);