open (USERS, ">", $users) or die "Cannot open $users: $!";
        foreach (@nup){
#       print "$genpass[0]\n";  <==this works
        s/xyz456/$genpass[0]/;  <==this gets uninitialized
        #print USERS;
        $a = shift(@genpass);
}


##</code><code>##

open (USERS, ">", $users) or die "Cannot open $users: $!";
foreach (@nup){
    chomp;
    print "$genpass[0]\n";   
    s/xyz456/$genpass[0]/;   
    #print USERS;
    $a = shift(@genpass);
}