swaygrab: Print usage and exit on unknown options

1 files changed, 12 insertions, 0 deletions

diff --git a/swaygrab/main.c b/swaygrab/main.c
index e60d154f..90d118e2 100644
--- a/swaygrab/main.c
+++ b/swaygrab/main.c
@@ -135,6 +135,15 @@ int main(int argc, char **argv) {
                 {0, 0, 0, 0}
         };
 
+        const char *usage =
+                "Usage: swaygrab [options] <output> [file]\n"
+                "\n"
+                "  -c, --capture          Capture video.\n"
+                "  -v, --version          Show the version number and quit.\n"
+                "  -s, --socket <socket>  Use the specified socket.\n"
+                "  -R, --rate <rate>      Specify framerate (default: 30)\n"
+                "  -r, --raw              Write raw rgba data to stdout.\n";
+
         int c;
         while (1) {
                 int option_index = 0;
@@ -165,6 +174,9 @@ int main(int argc, char **argv) {
 #endif
                         exit(EXIT_SUCCESS);
                         break;
+                default:
+                        fprintf(stderr, "%s", usage);
+                        exit(EXIT_FAILURE);
                 }
         }