print APPEND $line2
         if $line2 =~ /$line1/;

##</code><code>##

    $line1 = '1.2.3.4';
    $line2 = '111.2.3.44';
    print "match\n" if $line2 =~ /$line1/;

##</code><code>##

    $line1 = '1.2.3.4';
    $line2 = '11223344';
    print "match\n" if $line2 =~ /$line1/;