foreach $file ($afile, $bfile, $cfile, $dfile) {
    if (defined $file) {
        &parse_recent;
        &parse_monthly;
        &parse_new;
        &create_temp_a;
        &copy_new_to_recent;
        &copy_recent_to_monthly;
        &remove_excess; 
        &done; 
    }
}

##</code><code>##

&sub1("Good");

sub sub1 {
    &sub2;
}

sub sub2 {
    my $var = shift;
    print "We're having an argument: $var.\n" if defined $var;
}