TESTLINE [[nick!]user@]host

Looks up given mask, looking for any matching I/K/D/G lines.
If username is not specified, it will look up "dummy@host".
If nickname is specified it will also search for RESVs.

This command will not perform dns lookups on a host, for best
results you must testline a host and its IP form.

TESTLINE <#channel>

Shows whether the channel is reserved or not.
