You can get a listing of all other users on a channel with the /who command. An “@” next to a user name in the resulting report indicates that they are a channel operator, while a “*” next to their name indicates that they are an operator of the entire IRC network.
You can get information about a particular user with the /whois command. For example, to get information on the user “John5”, type the following:
You can see what information is recorded on yourself by trying the /whois on yourself — for example, if you are “piano7”:
The /who command all by itself, without a channel specified, will list everybody on the IRC network. The /whois command with an argument of “*” will produce the same effect. These commands are not recommended because the resulting reports will be very lengthy and will take a long time to be generated, possibly tieing up your client.
The /whowas command is the same as /whois, except that it is used for people who just left the network, and will return stored information from when they were logged on.