#!/usr/bin/perl

=head1 NAME

and - print lines that are present in one file and another

=head1 SYNOPSIS

and file

and [file|-] [file|-] ...

=head1 DESCRIPTION

B<and> reads the specified files and prints out the lines that are common
to all files, in the order they are listed in the last file. Use "-" to
make it read a file from standard input. If only one file is specified,
B<and> first reads standard input, and compares it with the specified file.

=head1 AUTHOR

Copyright 2006 by Joey Hess <joey@kitenet.net>

Licensed under the GNU GPL.

=cut

use warnings;
use strict;

if (@ARGV == 0) {
	die "usage: and [file|-] [file|-] ...\n";
}

if (@ARGV == 1) {
	unshift @ARGV, "-";
}

my %seen;
foreach my $fn (@ARGV) {
	open (IN, $fn) || die "and: read $fn: $!\n";
	while (<IN>) {
		chomp;
		$seen{$_}++;
		if ($seen{$_} == @ARGV) {
			print "$_\n";
		}
	}
	close IN;
}