Your concept should work, at least it's one possible solution. I would personally make a sort subroutine, and just pass commands to it.

#!/usr/bin/perl
# UNTESTED CODE
use strict;

$sortby = 'alpha'; # or num

my $network = sort($sortby);


sub sort {
  my $method = shift;
  my $sorted;

  $method = 'alpha' if ($method eq '');  # Default

  if ($method eq 'alpha') {
    $sorted = # alpha sort method
  } elsif ($method eq 'num') {
    $sorted = # num sort method
  } else {
    $sorted = "Error: No sort method defined!\n";
  }

  return $sorted;
}
[download]

I'm just curious to know if you've considered command line options? Rather than require the end user to manually edit the file every time, it would be worthwhile to utilize some sort of run-time configuration. Of course, you would always want to have some sort of default.

--Coplan