It so easy to do some things in Perl that very often, I don't even think of using external commands or exotic modules so my code is independant of anything but a vanilla Perl installation. I learn Perl in 1989 for that very reason: to forget about sed, cut, sort (...) while getting the benefit to already know since perl was conceptually reaped from them.

you don't need a sort because you assume your file(s) sorted; what a specious argument!!

-- stefp -- check out TeXmacs wiki