#!/usr/bin/perl
use warnings;
use strict;

my %myData= (
    'Method1' => {
        'Name' => 'ABC',
        'File' => 'Beta.dat',
        'Category' => 'Methods',
        'Params' => 'ARGV'
    },
    'Method2' => {
        'Name' => 'MNO',
        'File' => 'Alpha.dat',
        'Category' => 'Functions',
        'Params' => 'ARGV'
    },
    'Method3' => {
        'Name' => 'ABA',
        'File' => 'Beta.dat',
        'Category' => 'Methods',
        'Params' => 'ARGV'
    },
    'Method4' => {
        'Name' => 'MNZ',
        'File' => 'Alpha.dat',
        'Category' => 'Functions',
        'Params' => 'ARGV'
    }
    );

my @unsorted = keys %myData;

my @sorted = sort 
  { $myData{$a}{'Category'} cmp $myData{$b}{'Category'} or
    $myData{$a}{'File'} cmp $myData{$b}{'File'} or 
    $myData{$a}{'Name'} cmp $myData{$b}{'Name'} } @unsorted;


print join(' ', @sorted),"\n";

#prints
Method2 Method4 Method3 Method1
[download]

This works because cmp gives back 0 on equality. Which means that the 'or' doesn't short circuit and tests the next comparision.

I dropped the 'reverse' from the sort and exchanged $a and $b of the cmp instead.