When you say shell, do you means bash, csh, tcsh, ksh, zsh, or what? There is no automated way to convert from any of these shell languages to perl that I know of. The simplest way would be to look at the script, figure out how it works, and then rewrite it in Perl.

Hope this helps,,,

Aziz,,,

Update: There are also es, esh, eshell, kiss, lsh, pdksh, sash, and many more available on my Debian box.