->dir1->file.txt
->dir2->file.txt
->dir3->file.txt

##</code><code>##

->dir->file1.txt
     ->file2.txt
     ->file3.txt

##</code><code>##

->dir1->file1.txt
->dir2->file2.txt
->dir3->file3.txt

##</code><code>##

use File::Path qw/ make_path /;
make_path( $_ ) for 1 .. 20;