Indomitus beat me to the submit button, I see.

if($pword eq $cpword){
   open (FILE, "< memberlist.txt") or die $!;
    
   while(<FILE>){
      push @lines,$_;
   }
   close FILE or die $!;
}
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• You'll be able to zero in on problems like this if you habitually use the die statement, to test whether you've had success.
• Unless your passwords are numeric, you'll want to test equivalence with 'eq', unstead of '=='.
• And finally - your code closed the filehandle inside of your while loop (another thing that die would have told you).

if($pword==$cpword){
    
    open (FILE, "memberlist.txt");
    
    while(<FILE>){
    push @lines,$_;
    
    close FILE;
}    
}
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open (FILE, "memberlist.txt") || die "Cannot open: $!";
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• You can use @lines = <FILE> to get all the lines of a file in an array.
• You start off declaring variables with my, but then suddenly stop. Carry on doing it; also, use strict and don't use barewords like $cusr=bob, instead use $cusr='bob'.
• In my opinion, it's clearer to use <STDIN> whenever you're reading from standard input, apart from when you're using magic while (<>)

Edit kudra, 2001-11-04 Corrected markup

There are a few problems with the code you have posted (as noted by others and which I won't repeat here). However, once all of those little bugs are fixed you also might want to consider reworking the logic of the code. Here is a cleaned up version of your code, largely following your posted code in level and style (ie, not trying to add anything beyond what you are already doing), but rearranging the logic somewhat:

    #!/usr/bin/perl -w
    use strict;

    # first initialize necessary variables:
    my $err_msg = "Authorization Failed: please try again\n";
    my $cusr    = 'bob';
    my $cpword  = 'pass';

    # next obtain the user's data:
    my($usr, $pword);
    print "What is your username? ";
    $usr = <STDIN>;
    chomp($usr);

    print "Please enter your password:\n";
    $pword=<STDIN>;
    chomp($pword);  

    # now we can authenticate or die
    unless ($usr eq $cusr and $pword eq $cpword) {
        die $err_msg;
    }
    print "Authentication Complete!\n";

    # authorized file processing may ensue:
    my @lines;
    my $file = 'memberlist.txt';
    open (FILE, $file) || die "Can't open $file: $!";
    while(<FILE>){
        push @lines,$_;
    }       
    close FILE;

    # now do whatever with @lines.
    print @lines;
    __END__
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I am not saying the above is optimal --- it can be shortened and simplified further. But, we've now broken out the logic into 4 self contained tasks: 1)setting initial values, 2)obtaining user authentication data, 3)perform the authentication or die with a message, 4)read and otherwise process the file. In your original, those last three tasks were all intermixed in the code rather than proceeding logically from one stage to the next. This reordering not only reduces the complexity of the code (no more nested conditionals), it makes it easier to code and test section by section in the first place --- which can greatly help in avoiding (or at least catching early) the scattering of syntactical errors and ommissions that crept into your code. It is also good practice for when you want to break out logical tasks into subroutines.

I like how that is set up... it is a whole lot clearer than my jumbeled mess at the top, and for some reason the file output was still not working even after I changed it as stated above (however it was more likely due to flaws in my reproduction of the before stated code), so I very much appreciate the cleaned version, and I will work from there to add more on to this script. Oh, and thanks, now I understand unless statements a bit better, and see a reason for their existance (which I previously was searching for)Thanks again!

Make something idiot proof and they'll make a better idiot...