while (@array) {
     my $val = shift @array;
     # do something with $val
}

##</code><code>##

while (my $val = shift @array) {
     # ...
}

##</code><code>##

if (length $string) {
     # ...
}

##</code><code>##

open my $fh, "<", $file or die "failed to open $file $!";

##</code><code>##

$error_count++ and next if some_condition();

##</code><code>##

++$error_count and next if some_condition();