From add9d7fe4b0f0f856adc4fd390350d807204f70c Mon Sep 17 00:00:00 2001
From: David Sterba <dsterba@suse.cz>
Date: Mon, 8 Jun 2015 18:54:04 +0200
Subject: [PATCH] btrfs-progs: print compact help for btrfs

Running 'btrfs' without arguments will print complete help that spans
a lot of lines and is really helpful. Print only subcommand group
names with short descriptions, similar to what 'git' does.

Signed-off-by: David Sterba <dsterba@suse.cz>
---
 btrfs.c    |  2 +-
 commands.h |  1 +
 help.c     | 44 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 46 insertions(+), 1 deletion(-)

diff --git a/btrfs.c b/btrfs.c
index f0fa848b..63df377a 100644
--- a/btrfs.c
+++ b/btrfs.c
@@ -230,7 +230,7 @@ int main(int argc, char **argv)
 			if (!prefixcmp(argv[0], "--"))
 				argv[0] += 2;
 		} else {
-			usage_command_group(&btrfs_cmd_group, 0, 0);
+			usage_command_group_short(&btrfs_cmd_group);
 			exit(1);
 		}
 	}
diff --git a/commands.h b/commands.h
index bd23340d..f9733719 100644
--- a/commands.h
+++ b/commands.h
@@ -72,6 +72,7 @@ extern const char * const generic_cmd_help_usage[];
 void usage(const char * const *usagestr) __attribute__((noreturn));
 void usage_command(const struct cmd_struct *cmd, int full, int err);
 void usage_command_group(const struct cmd_group *grp, int all, int err);
+void usage_command_group_short(const struct cmd_group *grp);
 
 void help_unknown_token(const char *arg, const struct cmd_group *grp) __attribute__((noreturn));
 void help_ambiguous_token(const char *arg, const struct cmd_group *grp) __attribute__((noreturn));
diff --git a/help.c b/help.c
index 56aded3a..a67e3fdf 100644
--- a/help.c
+++ b/help.c
@@ -160,6 +160,50 @@ static void usage_command_group_internal(const struct cmd_group *grp, int full,
 	}
 }
 
+void usage_command_group_short(const struct cmd_group *grp)
+{
+	const char * const *usagestr = grp->usagestr;
+	FILE *outf = stdout;
+	const struct cmd_struct *cmd;
+
+	if (usagestr && *usagestr) {
+		fprintf(outf, "usage: %s\n", *usagestr++);
+		while (*usagestr)
+			fprintf(outf, "   or: %s\n", *usagestr++);
+	}
+
+	fputc('\n', outf);
+
+	fprintf(outf, "Command groups:\n");
+	for (cmd = grp->commands; cmd->token; cmd++) {
+		if (cmd->hidden)
+			continue;
+
+		if (!cmd->next)
+			continue;
+
+		fprintf(outf, "  %-16s  %s\n", cmd->token, cmd->next->infostr);
+	}
+
+	fprintf(outf, "\nCommands:\n");
+	for (cmd = grp->commands; cmd->token; cmd++) {
+		if (cmd->hidden)
+			continue;
+
+		if (cmd->next)
+			continue;
+
+		fprintf(outf, "  %-16s  %s\n", cmd->token, cmd->usagestr[1]);
+	}
+
+	fputc('\n', outf);
+	fprintf(stderr, "For an overview of a given command use 'btrfs command --help'\n");
+	fprintf(stderr, "or 'btrfs [command...] --help --full' to print all available options.\n");
+	fprintf(stderr, "Any command name can be shortened as far as it stays unambiguous,\n");
+	fprintf(stderr, "however it is recommended to use full command names in scripts.\n");
+	fprintf(stderr, "All command groups have their manual page named 'btrfs-<group>'.\n");
+}
+
 void usage_command_group(const struct cmd_group *grp, int full, int err)
 {
 	const char * const *usagestr = grp->usagestr;