+ "[-a]\n"
+ " print brief description of all commands\n"
+ " -a print description of subcommands too\n"
+ "help -fk keyword ...\n"
+ " print brief description of commands matching keyword\n"
+ " -f search keyword in command name\n"
+ " -k search keyword in command name and description\n"
+ "help [-a] command ...\n"
+ " print detailed usage of 'command'"