Problem
You want to check a specific number of arguments, have been supplied to your Perl script.
Solution
This snippet at the example tab, demonstrates how to check that 2 args, were postfixed to the Perl script.
If you only want to check one, then use ARGV!=0, for three 2, etc.
Example
Arguments are supplied via the ARGV array.
if($#ARGV!=1) { die("Usage: $0 ...n"); }