A few days ago I wrote about filtering referer spam from my server logs before they're processed by goaccess. goaccess doesn't support log filtering out of the box, but tools like grep or sed can be used to filter the log before it's processed by goaccess.

There are two main reports I use for this blog: today's log, and the last 30 days of activity.

Viewing today's log

This is nice and simple. It searches the log for entries that have today's date string, and the results are then piped to goaccess. 

grep "$(date '+%d\/%b\/%Y' -d 'today')" path/to/access_log \
    | goaccess -a

This can also be adapted to show log entries for a specific month (or year). I use this when generating monthly reports on how "Writing PHP with Emacs" is performing: 

grep 'Nov/2020' path/to/access_log \
    | grep "books/php-with-emacs" \
    | goaccess -a

Note: This could also be done in a single pass using grep's -e syntax, but I find this version more readable.

Viewing this month's log

This one is a little trickier as we need to filter out everything before a specific date. Thankfully sed can do this: 

sed -n '/'$(date '+%d\/%b\/%Y' -d '1 month ago')'/,$ p' path/to/access_log \
    | goaccess -a

There are a couple of parts here:

-n
This flag tells sed to hide its output. Normally it will display every line that is processed, which in this case would output the entire log file.
$(date '+%d\/%b\/%Y' -d '1 month ago')
This is evaluated and replaced by a timestamp for 1 month ago.
'/'$(date '+%d\/%b\/%Y' -d '1 month ago')'/,$ p'
This is the expression that sed will evaluate, which searches all entries that match a specific range. The , symbol is the range delimiter, and $ is the end of the range (which in this case is any date after the start date).
p
This final modifier tells sed to output lines that matched.

All together this filters log entries to the last 30 days before goaccess processes them. The date command is pretty flexible so this approach can filter entries to the current week, quarter, or any other range.