Gives a short listing of channels/categories, either beginning with a prefix 
or in a specified category. If no argument is given, lists all top-level 
categories. If an argument is given beginning with a #, lists all
channels starting with that prefix. If an argument is given not beginning 
with a #, that is assumed to be a category name, and it lists all channels
and categories in that channel. 

@listchannel knows the following flags:
  -name (don't trim long channel names)
  -topic (display name + topic (this is the default)) 
  -last (display name + last message time)
  -created (display name + create time)
  -byname  (sort by name)
  -bycreated (display channels from earliest-created to most-recently
	      created, instead of alphabetically.
  -bylast (display channels from least-used to most-recently-used,
           instead of alphabetically)
  -all (display all channels)
  -member (display channels of which you're a member)
  -nomember (display channels of which you're not a member)
  -tail  (display only last  lines of output)
  -categories (display all categories, or all categories in argument)
  -recent [] (display the last 10 (or ) talked-on channels; this is 
                 precisely an abbreviation for -all -bylast -tail )

You may specify the sort flags with + or - before their name, eg -byname or
+bylast. With +, byname sorts alphabetically and the others sort youngest to
oldest. With -, byname sorts reverse alphabetically, and the others sort
oldest to youngest. The default flags flags are +byname and -topic, unless 
you have the listflag field set on yourself, in which case that field's
value is taken as the default.


@listchannels unclassified (lists channels in the unclassified hierarchy)
@listchannels #s (prints only channels starting with "s")
@listchannels +bycreated (prints channels in order of creation time)
@listchannels -name +bylast #foo (etc)
@listchannels -recent (prints out last 10 channels talked on)
@listchannels -recent 20 (prints out last 20 channels talked on)
@listchannels -categories (prints out all categories)
@listchannels -categories ifmud (prints out all categories in ifmud)