What do each of the things in this line from my access log mean?
127.0.0.1 - - [05/Feb/2012:17:11:55 +0000] "GET / HTTP/1.1" 200 140 "-" "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.19 (KHTML, like Gecko) Chrome/18.0.1025.5 Safari/535.19"
You seem to be using the combined log format.
LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-agent}i\"" combined
"-"
otherwise.The complete(?) list of formatters can be found here. The same section of the documentation also lists other common log formats; readers whose logs don't look quite like this one may find the pattern their Apache configuration is using listed there.