The most horrid command to type in, but it will probably only be in makefiles anyway.
Standard input is an httpd log file.
Standard output is a version of the log file with the document name simplified if necessary, and the IP adderss turned into DNA name form if this is possible at the time. Checking DNS for every line of a 300k line file rather hammers it and is not considered friendly by DNS administrators, so there are various ways to use a local hosts file. Just look me up this IP address. Exits immediately after giving you the output. Many host files may be given with separate occurences of this option.