Exit with error if starting as 'arsh file' and file can't be opened

main.c

@@ -1004,7 +1004,7 @@ char* generate_ps1_prompt()
   }
   if(ps1_len < 2)
   {
-    copy_str_to_buf(prompt_buf, sizeof(prompt_buf), getenv("PS1"));
+    copy_str_to_buf(prompt_buf, sizeof(prompt_buf), env_buf);
     return prompt_buf;
   }
   size_t i = 1, j = 0;
@@ -1077,6 +1077,11 @@ int main(int argc, const char* argv[])
       stream = file;
       prompt = NULL;
     }
+    else
+    {
+      perror(argv[1]);
+      exit(1);
+    }
   }
 
   struct sigaction s;