fldiff

#!/usr/bin/perl -w

use strict;

my $sep = 'VS';

# Utility to diff two lists of files
# Example usage:
#  fldiff `grep Argpass * | cut -d: -f1 | uniq` VS `ls *.pm`
#  That'd find all .pm files that don't have the text "Argpass" in them...

main();

############################

sub main
{
my @args = @ARGV;
my ($list1, $list2) = get_lists_from_args(@args);
sorted_compare($list1, $list2);
}

sub usage
{
die "usage: fldiff FILES1.. $sep FILES2..\n\tFiles in list delimited by spaces\n";
}

sub get_lists_from_args
{
my (@args) = @_;
my @lists;
my $clist = 0;
foreach my $arg (@args)
	{
	if($arg eq $sep)
		{$clist++;next;}
	push(@{$lists[$clist]}, $arg);
	}
if( (! $lists[1]) || (! $lists[0]))
	{usage();}
my @l1 = sort @{$lists[0]};
my @l2 = sort @{$lists[1]};

return(\@l1, \@l2);
}

sub sorted_compare
{
my($l1, $l2) = @_;
# my @onlyl1;
# my @onlyl2;

while(@$l1 && @$l2)
	{ # Easy to compare two nonempty lists
	my $versus = $$l1[0] cmp $$l2[0];
	if($versus == 0)
		{ # Same element in each, quietly remove
		splice(@$l1, 0, 1);
		splice(@$l2, 0, 1);
		}
	elsif($versus < 0) # First list is first
		{
		my $just1 = splice(@$l1, 0, 1);
		# push(@onlyl1, $just1);
		print "<$just1\n";
		}
	else # $versus > 0, second list is first
		{
		my $just2 = splice(@$l2, 0, 1);
		# push(@onlyl2, $just2);
		print ">$just2\n";
		}
	}

if(@$l1)
	{
	foreach my $flentry (@$l1)
		{
		# push(@onlyl1, $flentry);
		print "<$flentry\n";
		}
	}

if(@$l2)
	{
	foreach my $flentry (@$l2)
		{
		# push(@onlyl2, $flentry);
		print ">$flentry\n";
		}
	}

}