As mentioned, if a command isn’t known by rcirc, it will simply be sent
along to the server. Some such commands are available on nearly all IRC
servers, such as:
/away ¶This sets your status as “being away” if you provide a reason, or sets
your status as “being back” if you do not. People can use the
C-c C-w command to check your status. Example: /away food.
Typical IRC servers implement many more commands. You can read more about the fantastic world of IRC online at the Internet Relay Chat (IRC) help archive.