init: add failed to start message

src/test/init.c

@@ -12,6 +12,10 @@
 void ls(char *dname) {
     while (dname[0] == ' ' && dname[0] != '\0') dname++;
     DIR *rfd = opendir(dname);
+    if (rfd == NULL) {
+        printf("Unknown directory: %s\n", dname);
+        return;
+    }
     struct dirent *cur = readdir(rfd);
     while (cur) {
         printf("%s\n", cur->d_name);
@@ -45,9 +49,11 @@ int main() {
         } else if (strcmp(line, "tasks") == 0) {
             print_tasks();
         } else {
-            if (fork() == 0)
+            if (fork() == 0) {
                 execve(line, 0, 0);
-            else
+                printf("Failed to start: %s\n", line);
+                return 0;
+            } else
                 wait(NULL);
         }
     }