The reason for preferring sed 42q instead of head -n 42 is because head didn't used to exist. IIRC it was created at Berkeley and for some years there were man

The reason for preferring sed 42q instead of head -n 42 is because head didn't used to exist. IIRC it was created at Berkeley and for some years there were many systems that didn't have it. It does seem a bit superfluous when all it could do was head -42 (the -n and other options came later). I still write sed 42q to this day. :)