tsort-check revision 1.2 
1#!/usr/bin/perl
2
3# Written by Marc Espie, 2001.
4# Public domain
5
6%order=();
7
8open(SORTED, shift) or die "No sorted output\n";
9while(<SORTED>) {
10	chomp;
11	$order{$_} = $i++;
12}
13close(SORTED);
14
15open(PAIRS, shift) or die "No pairs\n";
16while (<PAIRS>) {
17	chomp;
18	push(@pairs, split(/\s+/, $_));
19	while (@pairs >= 2) {
20	    ($a, $b) = (pop @pairs, pop @pairs);
21	    next unless $order{$a} < $order{$b};
22	    die "Bad pair $a $b\n";
23    	}
24}
25close(PAIRS);
26