diff --git a/init.source b/init.source
index b2cd850..e25fefd 100644
--- a/init.source
+++ b/init.source
@@ -91,7 +91,7 @@ fi
 ## extract command, very useful
 if [ "${JSTMBASH_GOODIES_EXTRACT}" == "true" ]; then
   function extract(){
-    if [ -n "${1}" ]; then
+    if [ -z "${1}" ]; then
       echo ":: Error: No file given."
       return 1
     fi