use warnings;
use strict;

my $file = '/tmp/test_file';

open FF, $file , or die "you suck\n";

while (<FF>) {
     next unless /XXXX/;
     $. += 1;  ### obviously this does not work ...
     print $_ ;

}

close (FF);

##</code><code>##

ZZZZZZZZZZZZ
YYYYY
XXXX
XX
XXXX
3333
ii
XXXX
asdfddd

##</code><code>##

XX
3333
asdfddd