Indeed a shell has no meat and must rely on many executable like grep, cut, sed, awl, find, ls. Beside the cost of paging them in (and out if you are really short on memory), there is the cost of forking them. Eventually there is the problem of portability. If you want to restrain yourself to the set of options supported identically everywhere, learning this set will cost you a lot. Better learn more of perl than to learn a subset that will bind one of you arm behind your back. And I forgot, even if you don't use them the features of these various command is there, you will have to carry them as extra luggage (bigger executable).

Except if you have to maintain existing shells, writing in Bourne shell or bash is a total loss except if people around you don't want to learn perl. But, in that case, this is not a technical limitation but a social one.

If there is a question, it is to choose between perl, python and ruby. I think with CPAN perl is still a winner even if it shows clear signs of entropy.

By the time ruby and python will have libraries as rich as CPAN, we will be using perl6. :)

-- stefp -- check out TeXmacs wiki