There's also this useful trick for writing perl scripts that will run using whatever is the first perl in the $PATH:

#!/bin/sh

exec perl -x $0

#!perl
# your perl code goes here
[download]

"But why not use #!/usr/bin/env perl?", I hear you cry.

Because env isn't always in /usr/bin - it's in /bin on some obscure platforms - and there can be "issues" with passing arguments to the executable via env.