if you have a script that makes heavy use of sed, awk, tr and the like, then maybe translating to perl would be most natural. but otherwise a script is either

if you have a script that makes heavy use of sed, awk, tr and the like, then maybe translating to perl would be most natural. but otherwise a script is either just calling a lot of commands one after the other, for which a shell script is fine. or they do a lot of data mangling without needing many external applications or none even, in which case any other languages besides perl is just as fine.