#!/usr/bin/perl

use strict;
use warnings;

my $d = qr/\d/;      #number
my $a = qr/[a-c]+/;  #alpha

while (<DATA>) {
    #while (  /($a)/g ) {
    #   print "$1\n";
    #}
    while ( /($a)/g || /($d)/g ) {  #<----won't work
    #while ( /($d)/g  ) {
        print "$1\n";
    }
}

__DATA__
1 a 2 aa 3 aaa
4 b 5 bb 6 bbb
7 c 8 cc 9 ccc