my $string = 'Long string' x 100000; sub psau() { print grep { /\b$$\b/ } `ps au` } # POSIX platforms sub bar { psau } sub foo { my $s = shift; psau } sub mod { my $s = shift; $s =~ s/Long/LONG/g; psau } psau; bar($string); foo($string); mod($string); psau;