diff --git a/src/Lib/Core.php b/src/Lib/Core.php
index 234c503..ba1ec74 100644
--- a/src/Lib/Core.php
+++ b/src/Lib/Core.php
@@ -19,6 +19,7 @@ use MadLisp\Reader;
 use MadLisp\Symbol;
 use MadLisp\Tokenizer;
 use MadLisp\UserFunc;
+use MadLisp\Vector;
 
 class Core implements ILib
 {
@@ -113,6 +114,24 @@ class Core implements ILib
             ));
         }
 
+        if (!$this->safemode) {
+            $env->set('system', new CoreFunc('system', 'Execute a command on the system.', 1, 1,
+                function (string $command) {
+                    // Use passthru to capture the raw output
+
+                    ob_start();
+                    passthru($command, $status);
+                    $output = ob_get_contents();
+                    ob_end_clean();
+
+                    return new Vector([
+                        $status,
+                        $output
+                    ]);
+                }
+            ));
+        }
+
         $env->set('throw', new CoreFunc('throw', 'Throw an exception. Takes one argument which is passed to catch.', 1, 1,
             function ($error) {
                 throw new MadLispUserException($error);