debian-cd-clone/tools/add_packages

#!/usr/bin/perl -w

use strict;

my $dir = shift;

if (! -d $dir) { 
	die "$dir is not a directory ..."; 
}

my $mirror  = $ENV{'MIRROR'}  || die "Set the MIRROR var ...\n";
my $localdebs = $ENV{'LOCALDEBS'} || $mirror;
my $nonus   = $ENV{'NONUS'}   || '';
my $basedir = $ENV{'BASEDIR'} || die "Set the BASEDIR var ...\n";

require "$basedir/tools/link.pl";

open (LIST, "$basedir/tools/apt-selection cache show @ARGV |") 
					|| die "Can't fork : $!\n";

$/ = ''; # Browse by paragraph

my ($p, $file, $arch, $d, $realfile, $source, $section, $name);
while (defined($_ = <LIST>)) {
	m/^Package: (\S+)/m and $p = $1;
	m/^Filename: (\S+)/mi and $file = $1;
	m/^Architecture: (\S+)/m and $arch = $1;
	m/^Section: (\S+)/m and $section = $1;

	$source = ($section =~ /non-US/) ? $nonus : $mirror;

	# This is a hack to allow the local debs to be located elsewhere.
	$source=$localdebs if $file=~m:local/:;

	# If arch=all and filename points to binary-all then create
	# a symbolic link in binary-$ARCH or if arch=all and filename is a
	# symbolic link we suppose that the link points to
	# .../binary-all/...  and we reproduce a similar setup on the CD
	if ($arch eq "all" and (-l "$source/$file" or 
	    			$file =~ m#/binary-all/#)) {
		$file =~ s#/binary-all/#/binary-$ENV{'ARCH'}/#g;
		if ($section =~ /non-US/) {
			$file =~ m#/([^/]+)$# and $name = $1;
			symlink ("../binary-all/$name", "$dir/$file");
		} else {
			$file =~ m#/([^/]+/[^/]+)$# and $name = $1;
			symlink ("../../binary-all/$name", "$dir/$file");
		}
		$file =~ s#/binary-$ENV{'ARCH'}/#/binary-all/#g;
	}
	# And we put the file in the CD tree (with a (hard) link)
	$realfile = real_file ("$source/$file");
	good_link ($realfile, "$dir/$file");
}

close LIST or die "Something went wrong with apt-cache : $@ ($!)\n";