You're not going to be able do this merely by running the script.

In order to efffect changes in your current shell environment, you will have to eval the output of your perl script, which should be valid shell syntax.

So, for example, with a script like this (called bubba.pl):

#!/usr/bin/perl

print "export BUBBA=gump\n";
[download]

You could set the environment in your bash-like shell like this:

  $ echo $BUBBA
  $ eval `bubba.pl`
  $ echo $BUBBA
  gump
[download]

The other option is to write the shell commands into a temporary file, then '.' execute that temporary file in your current script/environment.

Hope that helps,
Matt