#!/usr/bin/perl -w

use strict;

if (@ARGV < 2) {

	print STDERR "Usage: $0 <config1> <config2>\n";

	print STDERR "Merge kernel config files config1 and config2. " .

		     "Differences will be selected from config2.\n";

	exit 1;

}

my %config;

my @lines;

open CONFIG1, $ARGV[0]

    or die $ARGV[0] . ": $!\n";

while (<CONFIG1>) {

    push(@lines, $_);

    next unless /^(CONFIG_[A-Za-z0-9_]+)/ || /^# (CONFIG_[A-Za-z0-9_]+) is not set/;

    $config{$1} = $_;

}

close(CONFIG1);

open CONFIG2, $ARGV[1]

    or die $ARGV[1] . ": $!\n";

while (<CONFIG2>) {

    next unless /^(CONFIG_[A-Za-z0-9_]+)/ || /^# (CONFIG_[A-Za-z0-9_]+) is not set/;

    $config{$1} = $_;

}

close(CONFIG2);

foreach (@lines) {

    if (/^(CONFIG_[A-Za-z0-9_]+)/ || /^# (CONFIG_[A-Za-z0-9_]+) is not set/) {

	if (exists($config{$1})) {

	    print $config{$1};

	    delete $config{$1};

	}

    } else {

	print;

    }

}

foreach my $value (sort(values(%config))) {

	print $value;

}