my $match = 0;   # We haven't got a match yet.

while ($lines = <PSWD>){
   ($user,$pswd,$userID,$groupID,$info,$home,$shell) = split ':', $lines;

   if ($username eq $user) {
      print "Checking username... MATCH\n";     
      if ($passwd eq $pswd){
         print "Checking password... MATCH\n";
      }
      else {
         print "Password does not match!\n";
      }
      $match = 1; # We have found a match
      last;       # So stop looping already!
   }
}

unless ($match) {
   print "\"$username\" does not match any users in our database!\n";
}