/WHO [ [search-pattern] [ohurmaiMplf] ]
Looks up the information of users matching the range you provide. You may only /WHO nicknames in channels or on servers where you share a common channel with them, or ones which are not +i (unless you are an IRC operator). The search-pattern may be a special sequence of characters determined by the flags given below, or it may be one of a nickname, a channel, a hostmask, an ip address mask or a server mask.
The following flags after the mask have the following affects:
o Show online IRC operators matching the mask
u Unlimit the results past the maximum /who results value (IRC operators only)
r Show all users whos realnames match the mask. When this flag is set it overrides the meaning of the search-pattern, which must contain a glob pattern intended to match GECOS (realname) fields.
h Show real hostnames rather than masked hostnames (IRC operators only)
m Search for all users with a given set of user modes. When this flag is set it overrides the meaning of the search-pattern, which must contain the mode sequence to search for, for example to find all users with +i and without +s, issue the command WHO +i-s m.
a Show all users who's away message matches the given mask
p Show all users who are connected on the given port range
i Show all users whos ident (username) matches the given mask
M Show all users who have metadata attached to them with the given key name
l Show only local users
f Show only remote (far) users
You may combine multiple flags in one WHO command except where stated in the table above.
Show all local users with modes 'ix' but without mode 's'.
/WHO +ix-s ml
Show all users whos GECOS matches 'hiding*person' who are not on the local server
/WHO hiding*person rf
Show all users with SSL client certs (will not show any users unless you have an SSL module loaded)
/WHO ssl_cert M
Show all users connected on ports within the range 6660 through 6668, 6679 or 6680.
/WHO 6660-6668,6679,6680 p