IRC Server Reference Manual

The Basics
/join #channel Joins the specified channel.
/part #channel Leaves the specified channel.
/quit [message] Disconnects from current server with optional leaving message.
/server hostname Connects to the specified server.
/list Lists all channels on the current network.
/links Lists all servers on the current network. May be disabled "for security reasons".
/nick nickname Changes your nick.
/names #channel Shows the nicks of all users on #channel.
/msg nickname message Sends a private message to a user.
/query nickname message Sends a private message to a user and opens a private chat window.
/me action Prints "yourname action"
/notice nickname message Sends a notice to the specified user. Like a /msg, but usually makes a sound.
/whois nickname Shows information about the specified user. This action is not visible to the specified user.
/whowas nickname Shows information about a user who has quit.
/dns nickname Attempts to resolve the IP address of the specified user. Doesn't work on all networks, doesn't work all the time.
/ping nickname Pings the specified user. This action is visible to the specified user.

IRC Services (NickServ)
/msg NickServ register password [email] Registers your current nick with NickServ with the chosen password and binds it to an e-mail address (optional).
/msg NickServ identify password Identifies your nick to NickServ using the password you set.
/msg NickServ recover nickname password Kills (forcibly disconnects) someone who has your registered nick.
/msg NickServ ghost nickname password Terminates a "ghost" IRC session that's using your nickname.
/msg NickServ set password yournewpassword Changes your password.

IRC Services (ChanServ)
/msg ChanServ identify #channel Identifies you as the channel's founder and gives you founder-level privileges.
/msg ChanServ set #channel mlock modes Locks the channel's modes. Just + unlocks all.
/msg ChanServ set #channel secureops [on|off] Keeps everyone except aops, sops, and the founder from becoming ops.
/msg ChanServ set #channel keeptopic [on|off] Maintains the topic even if everyone leaves.
/msg ChanServ set #channel enforce [on|off] Restores op/halfop/voice if a person with op/halfop/voice gets de-opped/halfopped/voiced.
/msg ChanServ set #channel leaveops [on|off] Whether or not to allow the first person who join the channel to get ops.
/msg ChanServ register #channel password description Registers the current channel to you with ChanServ and sets its password and description.
/msg ChanServ drop #channel [dropcode] Un-registers the current channel to you with ChanServ.
/msg ChanServ set #channel founder [nickname] Sets the current channel's founder.
/msg ChanServ set #channel password [newpass] Changes the current channel's password to newpass.
/msg ChanServ set #channel desc [description] Changes the current channel's description.
/msg ChanServ set #channel url [address] Associates a URL with the channel.
/msg ChanServ set #channel [email@address] Associates an email address with the channel.

IRC Services (ChanServ modes)

 /msg ChanServ set [channel] mlock [-+mode]
+n Disallows external messages.
+t Only op/hops can set the topic.
+p Sets the channel as invisible in /list.
+s Sets the channel as invisible in /list and /whois.
+i Sets the channel as closed unless the person was invited.
+k [pass] Sets a password for the channel which users must enter to join.
+l [number] Sets a limit on the number of users who are allowed in the channel at the same time.
+m Prevents users who are not opped/hopped/voiced from talking.
+R Sets the channel so only registered nicks are allowed in.
+M Sets the channel so only registered nicks are allowed to talk.
+S Strips formatting from messages, rendering them as plaintext.
+C Blocks messages containing color codes.
+i A user must be invited to join the channel.
+N No nick changes permitted in the channel.