The problem with your first command is the "cut" - works great for a while. Then you deal with other_vhosts_combined.log, and there's a leading hostname and port, so you want -f2 instead. After that, you start working with the user-agent field, and after remembering that the date and request fields have internal spaces, settle for something like -f13, which works until someone puts a space in their faked-up referer, and you can't use cut any more.

I love plain-text logs, but that apache logformat is a bad example of "neatly delimited records", given the unstable mixture of spaces between and within fields (some of which are quoted, some not, and one even quoted with square brackets!).