SPECIFIERS
%x A date and time field matching the time-format and date-format variables. This is used when a timestamp is given instead of the date and time being in two separate variables.
%ttime field matching the time-format variable.
%ddate field matching the date-format variable.
%vThe server name according to the canonical name setting (Server Blocks or Virtual Host).
%eThis is the userid of the person requesting the document as determined by HTTP authentication.
%hhost (the client IP address, either IPv4 or IPv6)
%rThe request line from the client. This requires specific delimiters around the request (as single quotes, double quotes, or anything else) to be parsable. If not, we have to use a combination of special format specifiers as %m %U %H.
%qThe query string.
%mThe request method.
%UThe URL path requested.
Note: If the query string is in %U, there is no need to use %q. However, if the URL path, does not include any query string, you may use %q and the query string will be appended to the request.
%HThe request protocol.
%sThe status code that the server sends back to the client.
%bThe size of the object returned to the client.
%RThe "Referer" HTTP request header.
%uThe user-agent HTTP request header.
%DThe time taken to serve the request, in microseconds.
%TThe time taken to serve the request, in seconds with milliseconds resolution.
%L The time taken to serve the request, in milliseconds as a decimal number.
%^Ignore this field.
%~Move forward through the log string until a non-space (!isspace) char is found.
|Vertical pipe or bar is used for either the character prior to the vertical pipe or followed by the vertical pipe.