|laziness, impatience, and hubris|
Well your manager may be a moron, but I'm not sure "all the guys that like perl a lot say that it is better." will be very convincing....
Maybe it would be convincing to post to a shell scripting group so you can say. "The guys on the shell group say if you ***must*** pick one, perl is better."
It sounds kinda empirical to say stuff like:
CPAN has __ hundred thousand modules and libraries, all with search able on line, documentation and the biggest shell script repository has ___ hundred scripts.
Perl is more secure it has sandboxes like java and taint mode, and only interpolates once.
There are ____ books on perl at O'Relly and ___ books on shell
It takes ___ human (manager) readable lines of perl to do task ____ x and ____ lines of funky shell to do the same task