Another command you might find yourself needing somewhat often is the more command. The IRC protocol limits messages to 512 bytes, 60 or so of which must be devoted to some bookkeeping. Sometimes, however, Supybot wants to send a message that's longer than that. What it does, then, is break it into "chunks" and send the first one, following it with (X more messages) where X is how many more chunks there are. To get to these chunks, use the more command. One way to try is to look at the default value of supybot.replies.genericNoCapability--it's so long that it'll stretch across two messages:

  <jemfinch|lambda> $config default
                    supybot.replies.genericNoCapability
  <lambdaman> jemfinch|lambda: You're missing some capability
              you need. This could be because you actually
              possess the anti-capability for the capability
              that's required of you, or because the channel
              provides that anti-capability by default, or
              because the global capabilities include that
              anti-capability. Or, it could be because the
              channel or the global defaultAllow is set to
              False, meaning (1 more message)
  <jemfinch|lambda> $more
  <lambdaman> jemfinch|lambda: that no commands are allowed
              unless explicitly in your capabilities. Either
              way, you can't do what you want to do.

So basically, the bot keeps, for each person it sees, a list of "chunks" which are "released" one at a time by the more command. In fact, you can even get the more chunks for another user: if you want to see another chunk in the last command jemfinch gave, for instance, you would just say more jemfinch.