diff --git a/cmd/rng.c b/cmd/rng.c
index 2fb7202303a..4d91094a8ec 100644
--- a/cmd/rng.c
+++ b/cmd/rng.c
@@ -75,6 +75,6 @@ static int do_rng(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
 U_BOOT_CMD(
 	rng, 3, 0, do_rng,
 	"print bytes from the hardware random number generator",
-	"list         - list all the probed rng devices\n"
-	"rng [dev] [n]    - print n random bytes(max 64) read from dev\n"
+	"list          - list all probed rng devices\n"
+	"rng [dev [n]] - print n random bytes (max 64) read from dev\n"
 );
diff --git a/doc/usage/cmd/rng.rst b/doc/usage/cmd/rng.rst
index 4a61e33d272..c071f01e841 100644
--- a/doc/usage/cmd/rng.rst
+++ b/doc/usage/cmd/rng.rst
@@ -12,14 +12,14 @@ Synopsis
 ::
 
     rng list
-    rng [dev] [n]
+    rng [dev [n]]
 
 rng list
 --------
 
 List all the probed rng devices.
 
-rng [dev] [n]
+rng [dev [n]]
 -------------
 
 The *rng* command reads the random number generator(RNG) device and