diff --git a/test/functional/test_runner.py b/test/functional/test_runner.py
index 620554ffe4609..3ec46c76ac996 100755
--- a/test/functional/test_runner.py
+++ b/test/functional/test_runner.py
@@ -214,7 +214,7 @@ def main():
                                      epilog='''
     Help text and arguments for individual test script:''',
                                      formatter_class=argparse.RawTextHelpFormatter)
-    parser.add_argument('--combinedlogslen', '-c', type=int, default=0, help='print a combined log (of length n lines) from all test nodes and test framework to the console on failure.')
+    parser.add_argument('--combinedlogslen', '-c', type=int, default=0, metavar='n', help='On failure, print a log (of length n lines) to the console, combined from the test framework and all test nodes.')
     parser.add_argument('--coverage', action='store_true', help='generate a basic coverage report for the RPC interface')
     parser.add_argument('--exclude', '-x', help='specify a comma-separated-list of scripts to exclude.')
     parser.add_argument('--extended', action='store_true', help='run the extended test suite in addition to the basic tests')