This is a web application, right? For basic web authentication you may use .htaccess, described here. (off site link).

For dealing with account information per user, you may need to dig in a little deeper, actually learning Perl (or an other suitable language for CGI programming).

If you need help on some aspect of writing an access tool in Perl, let us know which step along the way you're hung up on. I would start by reading the documentation for CGI, and CGI::Session.

This is a web application, right? For basic web authentication you may use .htaccess

Good call. This way, you do not have to bother with authentication at all, as this will be handled by the web server. The downside is that you have no way to influence how the authentication dialog looks (the user's browser will produce one), but maybe this is not so important.

Once you protect your CGI script with basic web authentication, you can retrieve the user ID like this:

my $q = new CGI;
my $userid = $q->remote_user;
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You mean something like:

# Open file, loading passwords into a hash, keyed on usernames
my $filename = '/path/to/pw/file/outside/web/root/filename.extension';
my (%users);
open(DF, $filename) or die("Cannot open $filename for input: $!\n");
while (my $line = <DF>) {
  chomp($line);
  my @parts = split(/\|/, $line, 2);
  $users{$parts[0]} = $parts[1];
}
close(DF);

# Get parameters passed in
my $q = new CGI;
my $entered_un = $q->param('username');
my $entered_pw = $q->param('password');

# Test if username and password match
my $authorized = 0;
if (exists($users{$entered_un})) {
  # crypt() uses a 2-character salt for additional variation
  my $crypted_pw = crypt($users{$entered_un}, $entered_pw);
  if ($crypted_pw eq $users{$entered_un}) {
    $authorized++;
  }
}
if (! $authorized) {
  &display_incorrect_un_pw_msg;
  exit;
}

# do whatever, such as set a cookie or something, then whatever
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Code is untested, but should at least give you an idea of what is involved. Hope it helps.

   perldoc DBI
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HTH.