diff --git a/lib/parse/cmdline.py b/lib/parse/cmdline.py
index fb71e9860..5a2d15814 100755
--- a/lib/parse/cmdline.py
+++ b/lib/parse/cmdline.py
@@ -505,7 +505,7 @@ def parse_arguments():
         action="store",
         dest="output_format",
         metavar="FORMAT",
-        help=f"Report format (Available: {','.join(OUTPUT_FORMATS)})",
+        help=f"Report format (Available: {', '.join(OUTPUT_FORMATS)})",
     )
     output.add_option(
         "--log", action="store", dest="log_file", metavar="PATH", help="Log file"