if statement - Uninitialized Value on Perl code -

i have been looking @ code can't figure out following error: uninitialized value $match in string eq perl

basically code connects telnet several device , closes connection. test users , passwords see ones expired. when connects gives success message otherwise gives failure message.

i not know why giving me uninitialized value error. code using project:

$telnet = new net::telnet (     errmode => "return",      port => $puerto,      input_log => $output_log,      host => $host ); $conexion = $telnet -> open(timeout => 5); if ($conexion == 1) { print "se conecto al $host \n\n"; $input =  $telnet -> get(timeout => 10); if ($input) {     if ($input =~ /login name:/){         $cmd = $telnet -> print($user);         ($prematch, $match) = $telnet -> waitfor(                           timeout => 5,                            match => '/password:/');         if ($match) {             $cmd = $telnet -> print($password);             ($prematch, $match) = $telnet -> waitfor(                                  timeout => 5,                                   match => '/windows/');             if ($match) {                 $cmd = $telnet -> print("");                 ($prematch, $match) = $telnet -> waitfor(                                         timeout => 5,                                          match => '/choose/');                       # aca se tiene que diseñar el caso de errores de clave                     //////error line//////                 if ($match eq "choose") {                        //////error line//////                     $cmd = $telnet -> print("2");                     ($prematch, $match) = $telnet -> waitfor(                                                  timeout => 5,                                                   match => '/corp/');                     if ($match) {                         print "se autentico satisfactoriamente el usuario y la contrasena\n\n";                     }                 } else {                     print "el usuario o contrasena son erroneos, fallo la conexion\n\n";                     $cerrar = $telnet -> close;                     }                  }             }         }     }    } $cerrar = $telnet -> close; } 

i'm guessing

1. $telnet->waitfor() returned empty list
2. or @ list either 1 element
3. or perhaps undef value second element.

you see, "uninitialized" doesn't mean same thing means in other languages. might have had in $match before assigned undefined value. perl, whether or not ever defined value scalar, or assigned undefined value same.

that might of confusion is.

a lot of apis in perl return empty list, in list context, when fail. way "truth value" 0, can this:

unless (( $prematch, $match ) = $telnet->waitfor( timeout => 5, match => '/choose/' ))    {     die 'failed waiting telnet!'; }