Perl had numerous magic, one/two letter variables and copious regexp use, which is what gave it the line noise insult. Wtf is $@ and $_? After spending enough time breathing Perl you got a feel and could actually read it, but take a break and forget all the things, and it's back to being inscrutable. Meanwhile, the bash above isn't totally inscrutable. It's not python clear, and I don't know what SHLVL is without looking it up, but the rest is clear enough (awk with NR, isn't self explanatory, but unfortunately for me I've used too much awk).