describe: when failing, tell the user about options that work

diff --git a/builtin-log.c b/builtin-log.c
index 8d93c1a2a476c58991d779cd5168c36189fff766..25e21ed41534c8c3067c2e0d5afe4284faa2881a 100644 (file)
--- a/builtin-log.c
+++ b/builtin-log.c
@@ -27,6 +27,10 @@ static int default_show_root = 1;
 static const char *fmt_patch_subject_prefix = "PATCH";
 static const char *fmt_pretty;
 
+static const char * const builtin_log_usage =
+       "git log [<options>] [<since>..<until>] [[--] <path>...]\n"
+       "   or: git show [options] <object>...";
+
 static void cmd_log_init(int argc, const char **argv, const char *prefix,
                      struct rev_info *rev)
 {
@@ -69,6 +73,8 @@ static void cmd_log_init(int argc, const char **argv, const char *prefix,
                                die("invalid --decorate option: %s", arg);
                } else if (!strcmp(arg, "--source")) {
                        rev->show_source = 1;
+               } else if (!strcmp(arg, "-h")) {
+                       usage(builtin_log_usage);
                } else
                        die("unrecognized argument: %s", arg);
        }