Hi

But i don't know how to make it to search in every folder.
One of the ways of doing that, is using either a recursive subroutine, or use File::Find module.
Using a recursive subroutine:
For Example: To list out all the files in different folders in a directory like so:

use warnings;
use strict;

scan_dir( $ARGV[0] );    ## call subroutine

sub scan_dir {
    my ($dir) = @_;
    if ( -d $dir ) {     ## check if directory
        opendir my $dh, $dir or die "can't open directory: $!";
        while ( readdir $dh ) {
            next if $_ eq '.' or $_ eq '..';
            print $_, $/;
            scan_dir("$dir/$_");    ## recursive call
        }
    }
}
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This can even get simplier using a File::Find module like so:

use warnings;
use strict;
use File::Find qw(find);

  find(\&scan_dir,$ARGV[0]);

  sub scan_dir{
     return if $_ eq '.' or $_ eq '..';
    print $_,$/;
   }
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NOTE:Please, that the codes above is to show how you can transverse a dircetory. To get your rar files, and "unrar", is left for you to figure out. Am sure you will get around it! :)
Check perldoc File::Find for more info.
Cheers.