1 files changed, 1 insertions, 0 deletions
diff --git a/src/aardig.c b/src/aardig.c
index 5772054..0388782 100644
--- a/src/aardig.c
+++ b/src/aardig.c
@@ -41,6 +41,7 @@ static char** parse_options(int argc, char **argv, int *niceness) {
         exit(0);
 
       case '?':
+        fprintf(stderr, "aardig: Ongeldige optie: -%c\n", optopt);
         usage(stderr);
         exit(1);
     }