static const char *parse_cmd_option(struct strbuf *input, const char *next)
 {
-       if (!strncmp(next, "no-deref", 8) && next[8] == line_termination)
+       const char *rest;
+       if (skip_prefix(next, "no-deref", &rest) && *rest == line_termination)
                update_flags |= REF_NO_DEREF;
        else
                die("option unknown: %s", next);
-       return next + 8;
+       return rest;
 }
 
 static void update_refs_stdin(struct ref_transaction *transaction)
                        die("empty command in input");
                else if (isspace(*next))
                        die("whitespace before command: %s", next);
-               else if (starts_with(next, "update "))
-                       next = parse_cmd_update(transaction, &input, next + 7);
-               else if (starts_with(next, "create "))
-                       next = parse_cmd_create(transaction, &input, next + 7);
-               else if (starts_with(next, "delete "))
-                       next = parse_cmd_delete(transaction, &input, next + 7);
-               else if (starts_with(next, "verify "))
-                       next = parse_cmd_verify(transaction, &input, next + 7);
-               else if (starts_with(next, "option "))
-                       next = parse_cmd_option(&input, next + 7);
+               else if (skip_prefix(next, "update ", &next))
+                       next = parse_cmd_update(transaction, &input, next);
+               else if (skip_prefix(next, "create ", &next))
+                       next = parse_cmd_create(transaction, &input, next);
+               else if (skip_prefix(next, "delete ", &next))
+                       next = parse_cmd_delete(transaction, &input, next);
+               else if (skip_prefix(next, "verify ", &next))
+                       next = parse_cmd_verify(transaction, &input, next);
+               else if (skip_prefix(next, "option ", &next))
+                       next = parse_cmd_option(&input, next);
                else
                        die("unknown command: %s", next);