diff --git a/diff.c b/diff.c
index ccfa1fc..e50def4 100644
--- a/diff.c
+++ b/diff.c
@@ -5590,7 +5590,7 @@
 		OPT_BITOP(0, "shortstat", &options->output_format,
 			  N_("output only the last line of --stat"),
 			  DIFF_FORMAT_SHORTSTAT, DIFF_FORMAT_NO_OUTPUT),
-		OPT_CALLBACK_F('X', "dirstat", options, N_("<param1,param2>..."),
+		OPT_CALLBACK_F('X', "dirstat", options, N_("<param1>,<param2>..."),
 			       N_("output the distribution of relative amount of changes for each sub-directory"),
 			       PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
 			       diff_opt_dirstat),
@@ -5598,8 +5598,8 @@
 			       N_("synonym for --dirstat=cumulative"),
 			       PARSE_OPT_NONEG | PARSE_OPT_NOARG,
 			       diff_opt_dirstat),
-		OPT_CALLBACK_F(0, "dirstat-by-file", options, N_("<param1,param2>..."),
-			       N_("synonym for --dirstat=files,param1,param2..."),
+		OPT_CALLBACK_F(0, "dirstat-by-file", options, N_("<param1>,<param2>..."),
+			       N_("synonym for --dirstat=files,<param1>,<param2>..."),
 			       PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
 			       diff_opt_dirstat),
 		OPT_BIT_F(0, "check", &options->output_format,