Simple Hash Question

[walkingthecow]

Hey monks,

I have a subroutine that builds a command. It allows for users to re-enter input if they happen to mess up. I have no problem building everything from input, however, I am not sure how to build the flag if someone passes the variables to the subroutine.

Basically, I am trying to allow the flags to be passed to the subroutine (e.g., buildCommand("bobjones"); ), but if they send that to the subroutine at this point, nothing gets returned...

UPDATE
Sorry, I forgot about the title... Woops! Well, the reason I said "Simple Hash Question" is because I was thinking that maybe it'd be easier to build the flags as a hash and then return them. As you can see, if $user gets passed at this point, it will never be added to $flag as "-user $user". In order for this to occur the individual must select option 1 and then enter the user, even after it is passed. This is obviously because anything passed to the subroutine is not evaluated. I was thinking I could do it this way (see CODE below ORIGINAL CODE) with scalars, but there must be an easier way to do it, possibly with a hash...

ORIGINAL CODE

sub buildCommand {
    my ($user,$uid,$group,$home,$create,$shell)=@_;
    my $flag;

    while (1) {
       print qq {
1. User:        $user
2. UID:         $uid
3. Group:       $group
4. Home Dir:    $home
5. Comment:     $comment
6. Shell:       $shell

D. Done
};

       print "Please Choose An Option From Above: "
       chomp(my $ans=<STDIN>);

       if ($ans == 1) {
          $user = getInput("Enter Username: ");
          $flag = "-user $user";
       }
       elsif ($ans == 2) {
          $uid = getInput("Enter UID: ");
          $flag .= " -uid $uid";
       }
       elsif ($ans == 3) {
          $group = getInput("Enter Group: ");
          $flag .= " -group $group";
       }
       elsif ($ans == 4) {
          $home = getInput("Enter Home: ");
          $flag .= " -home $home";
       }
       elsif ($ans == 5) {
          $comment = getInput("Enter Comment: ");
          $flag .= " -comment $comment";
       }
       elsif ($ans == 6) {
          $shell = getInput("Enter Shell: ");
          $flag .= " -shell=$shell";
       }
       elsif ($ans =~ /d/i && defined($user)) {
          return($flag);
       }
       else {
          print "INVALID OPTION!\n";
       }
    }
}

WORKING (BUT NOT VERY GOOD) WAY OF DOING IT

sub buildCommand {
    my ($user,$uid,$group,$home,$create,$shell)=@_;
    my $flag;

    while (1) {
       print qq {
1. User:        $user
2. UID:         $uid
3. Group:       $group
4. Home Dir:    $home
5. Comment:     $comment
6. Shell:       $shell

D. Done
};

       print "Please Choose An Option From Above: "
       chomp(my $ans=<STDIN>);

       if ($ans == 1) {
          $user = getInput("Enter Username: ");
       }
       elsif ($ans == 2) {
          $uid = getInput("Enter UID: ");
       }
       elsif ($ans == 3) {
          $group = getInput("Enter Group: ");
       }
       elsif ($ans == 4) {
          $home = getInput("Enter Home: ");
       }
       elsif ($ans == 5) {
          $comment = getInput("Enter Comment: ");
       }
       elsif ($ans == 6) {
          $shell = getInput("Enter Shell: ");
       }
       elsif ($ans =~ /d/i && defined($user)) {
          last;
       }
       else {
          print "INVALID OPTION!\n";
       }
    }
    if (defined($user)) {
       $flag = "-user $user";
    }
    if (defined($uid)) {
       $flag = " -uid $uid";
    }
    if (defined($group)) {
       $flag = " -group $group";
    }
    if (defined($home)) {
       $flag = " -home $home";
    }
    if (defined($comment)) {
       $flag .= " -comment $comment";
    }
    if (defined($shell)) {
       $flag .= " -shell $shell";
    }
    return($flag);
}

[targetsmart]

IMO your subroutine seems to be fine
however, you may have problems in the place where you are calling this subroutine
at all these tough times, perl -d is your helper; use it; see perldebug
BTW your post title, 'simple hash question' seems to be irrelevant to the post!.


UPDATE
good that you know you can use hashes, why you have not tried it?.
see here about hashes
for your case you can use some thing like below


my %flag;
..
$flag{'user'} = $user;
..
$flag{'uid'} = $uid;
...
...
return %flag; 

at the calling place use
my %userflags = buildCommand(..)
then access the values like $userflags{'user'}

or use references

return \%flag;

at the calling place use
my $userflags = buildCommand(..)
then access the values like $userflags->{'user'}

see perlref for more details on references.
learning perl is a good place to start.

[walkingthecow]

Hm, so I am still at a roadblock here. I guess I do not understand how I would do it... Here is what I have, but as you can see I still have to evaluate what comes in... The problem is, this: "my ($user,$uid,$group,$home,$create,$shell)=@_;" is not doing anything at all. It is never evaluated, and I am unsure a nice clean way of doing that.

sub buildCommand {
    my ($user,$uid,$group,$home,$create,$shell)=@_;
    my %flag;

    while (1) {
       print qq {
1. User:        $user
2. UID:         $uid
3. Group:       $group
4. Home Dir:    $home
5. Comment:     $comment
6. Shell:       $shell

D. Done
};

       print "Please Choose An Option From Above: "
       chomp(my $ans=<STDIN>);

       if ($ans == 1) {
          $flag{'user'} = getInput("Enter Username: ");
       }
       elsif ($ans == 2) {
          $flag{'uid'} = getInput("Enter UID: ");
       }
       elsif ($ans == 3) {
          $flag{'group'} = getInput("Enter Group: ");
       }
       elsif ($ans == 4) {
          $flag{'home'} = getInput("Enter Home: ");
       }
       elsif ($ans == 5) {
          $flag{'comment'} = getInput("Enter Comment: ");
       }
       elsif ($ans == 6) {
          $flag{'shell'} = getInput("Enter Shell: ");
       }
       elsif ($ans =~ /d/i && defined($user)) {
          last;
       }
       else {
          print "INVALID OPTION!\n";
       }
    }
    while (($key, $value) = each(%flag)){
        $flag .= "-$key $value ";
    }
    return(%flag);
}