The format to use when logging accesses. The syntax is:
response-code or *: Log format for that response acode
Log format is normal characters, or one or more of the variables below:
$host -- The remote host name, or ip number.
$ip_number -- The remote ip number.
$bin-ip_number -- The remote host id as a binary integer number.
$cern_date -- Cern Common Log file format date.
$bin-date -- Time, but as an 32 bit iteger in network byteorder
$method -- Request method
$resource -- Resource identifier
$protocol -- The protocol used (normally HTTP/1.0)
$response -- The response code sent
$bin-response -- The response code sent as a binary short number
$length -- The length of the data section of the reply
$bin-length -- Same, but as an 32 bit iteger in network byteorder
$referer -- the header 'referer' from the request, or '-'.
$user_agent -- the header 'User-Agent' from the request, or '-'.
$user -- the name of the auth user used, if any