my $folder = '//..';
find (\&process, $folder);
sub process
{
        if ( $File::Find::name =~ /\learn$/ ) {
        open (FILE, $File::Find::name ) or
        die "Cannot open file: $!";
while (  $line = <FILE> ) {
 
$/= "# input for";

$line  =~  s/.....;

push(@outLines, $line );
        }
       print to outputfile...
}
}