How can I list files under a directory with a specific name pattern using Perl?

Question

I have a directory /var/spool and inside that, directories named

a  b  c  d  e  f  g  h i  j  k  l  m  n  o  p q  r  s  t  u  v  x  y z

And inside each "letter directory", a directory called "user" and inside this, many directories called auser1 auser2 auser3 auser4 auser5 ...

Every user directory contains mail messages and the file names have the following format: 2. 3. 4. 5. etc.

How can I list the email files for every user in every directory in the following way:

    /var/spool/a/user/auser1/11.
    /var/spool/a/user/auser1/9.
    /var/spool/a/user/auser1/8.
    /var/spool/a/user/auser1/10.
    /var/spool/a/user/auser1/2.
    /var/spool/a/user/auser1/4.
    /var/spool/a/user/auser1/12.
    /var/spool/b/user/buser1/12.
    /var/spool/b/user/buser1/134.
    /var/spool/b/user/buser1/144.

etc.

I need that files and then open every single file for modify the header and body. This part I already have, but I need the first part.

I am trying this:

dir = "/var/spool";

opendir ( DIR, $dir ) || die "No pude abrir el directorio $dirname\n";
while( ($filename = readdir(DIR))){
    @directorios1 = `ls -l "$dir/$filename"`;
    print("@directorios1\n");
}
closedir(DIR);

But does not work the way I need it.

Answer 1

As others have noted, use File::Find:

#!/usr/bin/perl

use strict;
use warnings;

use File::Find;

find(\&find_emails => '/var/spool');

sub find_emails {
    return unless /\A[0-9]+[.]\z/;
    return unless -f $File::Find::name;

    process_an_email($File::Find::name);
    return;
}

sub process_an_email {
    my ($file) = @_;
    print "Processing '$file'\n";
}