A shell script in as much as a shell script is the combination of a text file containing a set of commands (each of which is individually runnable at the shell prompt) run by an instance of the shell interpreter.

I've always considered a perl script to be a specialization of a shell script in as much as the perl script ...

1. only contains perl commands and ...
2. uses the perl interpreter to run the script.

The normal way in which a script is made runnable in its' own right is to...

• chmod(1) the script file to give it execute rights c/w ...
• putting #! /usr/bin/sh (the shebang or hash-bang line) at the very top of the file

So, in order to convert your script (after granting execute rights to the script (via chmod +x file), add the following at the very top of your script file:

#! /usr/bin/env perl
[download]

Does that help ??