diff --git a/src/CliPrompt.php b/src/CliPrompt.php
index b781a8d..9fdef58 100644
--- a/src/CliPrompt.php
+++ b/src/CliPrompt.php
@@ -59,17 +59,19 @@ public static function hiddenPrompt($allowFallback = false)
                 $exe = $tmpExe;
             }
 
-            $answer = self::trimAnswer(shell_exec($exe));
+            $output = shell_exec($exe);
 
             // clean up
             if (isset($tmpExe)) {
                 unlink($tmpExe);
             }
 
-            // output a newline to be on par with the regular prompt()
-            echo PHP_EOL;
+            if ($output !== null) {
+                // output a newline to be on par with the regular prompt()
+                echo PHP_EOL;
 
-            return $answer;
+                return self::trimAnswer($output);
+            }
         }
 
         if (file_exists('/usr/bin/env')) {
@@ -85,12 +87,14 @@ public static function hiddenPrompt($allowFallback = false)
             if (isset($shell)) {
                 $readCmd = ($shell === 'csh') ? 'set mypassword = $<' : 'read -r mypassword';
                 $command = sprintf("/usr/bin/env %s -c 'stty -echo; %s; stty echo; echo \$mypassword'", $shell, $readCmd);
-                $value = self::trimAnswer(shell_exec($command));
+                $output = shell_exec($command);
 
-                // output a newline to be on par with the regular prompt()
-                echo PHP_EOL;
+                if ($output !== null) {
+                    // output a newline to be on par with the regular prompt()
+                    echo PHP_EOL;
 
-                return $value;
+                    return self::trimAnswer($output);
+                }
             }
         }