The for loop will not loop more than once due to the return statement. What's more, the following code, which prints out the usage, also won't run. Let's change this to look more like other commands. Print out invalid options and then print out the usage. usage_with_options will exit, so no need for a return there. Signed-off-by: Jeff Moyer <jmoyer(a)redhat.com&gt; diff --git a/daxctl/io.c b/daxctl/io.c index 27e7463..2f8cb4a 100644 --- a/daxctl/io.c +++ b/daxctl/io.c @@ -526,15 +526,11 @@ int cmd_io(int argc, const char **argv, void *daxctl_ctx) struct ndctl_ctx *ndctl_ctx; argc = parse_options(argc, argv, options, u, 0); - for (i = 0; i < argc; i++) { + for (i = 0; i < argc; i++) fail("Unknown parameter \"%s\"\n", argv[i]); - return -EINVAL; - } - if (argc) { + if (argc) usage_with_options(u, options); - return 0; - } if (!io.dev[0].parm_path && !io.dev[1].parm_path) { usage_with_options(u, options);