New subcommand: help.

It's sometimes handy to just type e.g. "dss help run" to see the
synopsis and the options of the ls subcommand.

diff --git a/dss.c b/dss.c
index 7a64346a525063daece9b45e4a10b515cf243622..477df6f1a5f3e8f356af352e400a0ee73dcdf6ac 100644 (file)
--- a/dss.c
+++ b/dss.c
@@ -1834,15 +1834,18 @@ static void handle_version_and_help(void)
 {
        char *txt;
 
+       if (OPT_GIVEN(DSS, VERSION)) {
+               printf("%s\n", dss_version());
+               exit(EXIT_SUCCESS);
+       }
        if (OPT_GIVEN(DSS, DETAILED_HELP))
                txt = lls_long_help(CMD_PTR(DSS));
        else if (OPT_GIVEN(DSS, HELP))
                txt = lls_short_help(CMD_PTR(DSS));
-       else if (OPT_GIVEN(DSS, VERSION))
-               txt = make_message("%s\n", dss_version());
        else
                return;
        printf("%s", txt);
+       printf("\nRun dss help for help on subcommands.\n");
        free(txt);
        exit(EXIT_SUCCESS);
 }
@@ -1858,8 +1861,39 @@ static void show_subcommand_summary(void)
                const char *purpose = lls_purpose(cmd);
                printf("%-11s%s\n", name, purpose);
        }
-       exit(EXIT_SUCCESS);
+       printf("\nRun dss help <subcmd> for help on <subcmd>.\n");
+}
+
+static int com_help(void)
+{
+       int ret;
+       char *errctx, *help;
+       const char *arg;
+       const struct lls_command *cmd;
+
+       ret = lls_check_arg_count(sublpr, 0, 1, &errctx);
+       if (ret < 0)
+               return lopsub_error(ret, &errctx);
+       if (lls_num_inputs(sublpr) == 0) {
+               show_subcommand_summary();
+               return 0;
+       }
+       arg = lls_input(0, sublpr);
+       ret = lls_lookup_subcmd(arg, dss_suite, &errctx);
+       if (ret < 0)
+               return lopsub_error(ret, &errctx);
+       cmd = lls_cmd(ret, dss_suite);
+       if (OPT_GIVEN(HELP, LONG))
+               help = lls_long_help(cmd);
+       else
+               help = lls_short_help(cmd);
+       printf("%s", help);
+       free(help);
+       if (!OPT_GIVEN(HELP, LONG))
+               printf("\nRun dss -- help -l %s for long help.\n", arg);
+       return 0;
 }
+EXPORT_CMD_HANDLER(help);
 
 int main(int argc, char **argv)
 {
@@ -1880,8 +1914,11 @@ int main(int argc, char **argv)
                goto out;
        handle_version_and_help();
        num_inputs = lls_num_inputs(lpr);
-       if (num_inputs == 0)
+       if (num_inputs == 0) {
                show_subcommand_summary();
+               ret = 0;
+               goto out;
+       }
        ret = lls_lookup_subcmd(argv[argc - num_inputs], dss_suite, &errctx);
        if (ret < 0) {
                ret = lopsub_error(ret, &errctx);

diff --git a/dss.suite.m4 b/dss.suite.m4
index 27437f443563c8ea146f7732a9c700bdabad4392..3fe3122b6b619bcfa600a4ce61ab31b292f4415a 100644 (file)
--- a/dss.suite.m4
+++ b/dss.suite.m4
@@ -526,9 +526,25 @@ caption = Subcommands
                exits successfully or prints information about the first syntax error
                detected and terminates with exit code 1.
        [/description]
+[subcommand help]
+       purpose = list available subcommands or print subcommand-specific help
+       non-opts-name = [subcommand]
+       [description]
+               If the optional subcommand argument is given, the help text of that
+               subcommand is shown. Without the argument the available subcommands
+               are listed instead.
+       [/description]
+       [option long]
+               short_opt = l
+               summary = show the long help text of a subcommand
+               [help]
+                       If this option is given, the command also shows the description of
+                       the subcommand and the help text of each option, Otherwise only the
+                       purpose, the synopsis and the option list of the subcommand is shown.
+                       If no subcommand is supplied, the option has no effect.
+               [/help]
 
 [section examples]
-
        Suppose you'd like to create snapshots of the existing directory
        .I /foo/bar
        in the directory