#!/usr/bin/perl -w
#
# Run a command on all lexically-ordered pairs of filenames in the
# list given.  That is, ('a', 'b') is a pair but ('b', 'a') won't be
# run because 'a' comes before 'b' alphabetically.
#
# Part of similarity-utils version 0.1.
#
use strict;
die "usage: $0 prog files...\nfor 'prog', try 'similarity' or 'similarity_by_diff'\n"
  if @ARGV < 3;
my $prog = shift @ARGV;
my @files = grep { -f or warn("skipping non-file $_\n"), 0 } @ARGV;
I: foreach my $i (@files) {
    J: foreach my $j (@files) {
	next unless $i lt $j;
	system($prog, $i, $j) && die "running $prog $i $j failed: $!";
    }
}