irssi/docs/help/in/mode.in

@SYNTAX:mode@

Both channels and users have modes associated with them. For channels, 
they determine who is a channel operator, the number of people who may
join the channel, who may not enter the channel, and myriad other things. 
For users, they determine whether the user is an IRC operator, whether 
the user will receive special server notices, etc. 

Modes are enabled when prepended with a "+", and disabled when with a "-". 

Standard User Modes: 
     i    When enabled, you are "invisible" to NAMES and WHO queries from 
          anyone not on a channel common to you. Additionally, you are also 
          hidden from WHOIS unless you exact nickname is specified. 
     o    When enabled, this gives you IRC operator status.
     s    When enabled, you will receive special server notices.
     w    When enabled, you will receive IRC operator WALLOPS, as well as 
          notices of any remote CONNECTs or SQUITs. 

Standard Channel Modes: 
     b    When enabled, this prevents the specified nick!user@host mask from 
          entering the channel. 
     i    When enabled, users may only join the channel if INVITEd. 
     k    When enabled, users may only join the channel if they specify the 
          proper "key".
     l    When enabled, only the specified number of users may enter the channel. 
     m    When enabled, only users with +o or +v may speak on the channel. 
     n    When enabled, public messages from outside the channel are not allowed. 
     o    When enabled, grants the specified nickname channel operator status. 
     p    When enabled, the channel is made private. The channel name will not show 
          up in WHO, WHOIS, NAMES, or LIST replies.
     s    When enabled, makes the channel secret. This is the same as +p, except 
          the channel will not show up in any WHO/WHOIS /etc. queries from a 
          person not on the channel. Anyone who is on a +s channel is effectively 
          invisible, as per user mode +i. 
     t    When enabled, only channnel operators may set a topic. 
     v    When enabled, grants the specified nickname voice status. 

Examples: 
   /MODE your_nick +sw    - Receive operator WALLOPS and server notices 
   /MODE your_nick +s+w     (both examples are equivalent). 
   /MODE #channel +l 35   - Set a channel limit
   /MODE #channel +o theirnick 
                          - Make theirnick a channel operator.
   /MODE #channel +bk-o *!*some@*.ban.com Secret_Key foobar 
                          - Set a ban, a key, and remove chanop status 
                            from 'foobar'. 

See also: BAN, VOICE, OP, DEOP, INVITE