It has:
* The subcommand `set` to save new values.
* The subcommand `get` to read existing values.
* The subcommand `list` to see all available keys.
* The subcommand `rename` to change keys' names.
* The subcommand `remove` to destroy existing keys or all of them.
* The subcommand `exec` to execute values as commands.
* The subcommand `snippet` to use values with changing content.
* The option `--help` message and one per subcommand.
* Use `~/.slate` file as main storage point.