1 files changed, 3 insertions, 3 deletions

diff --git a/src/cdf.c b/src/cdf.c
index 3bf39fe..2b26e27 100644
--- a/src/cdf.c
+++ b/src/cdf.c
@@ -18,7 +18,7 @@ static int parse_options(int argc, char *const *argv) {
   int arg;
   bool error = false;
 
-  while ((arg = getopt(argc, argv, "frhu")) != -1) {
+  while ((arg = getopt(argc, argv, "frhu")) != -1 && !error) {
     switch (arg) {
     case 'f':
       ARG_FP_INPUT = true;
@@ -34,9 +34,9 @@ static int parse_options(int argc, char *const *argv) {
       break;
     case '?':
       if (isprint(optopt)) {
-        fprintf(stderr, "Unknown option `-%c`.\n", optopt);
+        fprintf(stderr, "Error: unknown option `-%c`.\n", optopt);
       } else {
-        fprintf(stderr, "Unknown option character `\\x%x`.\n", optopt);
+        fprintf(stderr, "Error: unknown option character `\\x%x`.\n", optopt);
       }
       error = true;
       break;