Add required argument to cli parameter
diff --git a/README.md b/README.md
index b848ce6..fc574ed 100644
--- a/README.md
+++ b/README.md
@@ -58,9 +58,9 @@
- `detect-aws-credentials` - Checks for the existence of AWS secrets that you
have set up with the AWS CLI.
The following arguments are available:
- - `--credentials-file` - additional AWS CLI style configuration file in a
- non-standard location to fetch configured credentials from. Can be repeated
- multiple times.
+ - `--credentials-file CREDENTIAL_FILES` - additional AWS CLI style
+ configuration file in a non-standard location to fetch configured
+ credentials from. Can be repeated multiple times.
- `--allow-missing-credentials` - Allow hook to pass when no credentials are
detected.
- `detect-private-key` - Checks for the existence of private keys.
