Maintain specific log file

Is it possible to maintain a specific log file? I want to keep 7 days worth of a specific log file. Is it possible to do this or do I need to go to full logging for all logs?

The other query is over the ramlog #2 - does this save files incrementally or does each write to disk overwrite the existing file?

Cheers

Hi

The other query is over the ramlog #2 - does this save files incrementally or does each write to disk overwrite the existing file?

This would do it if you still want benefit of DietPi-RAMlog.
All current logs are appended to /root/logfile_storage, before /var/log is cleared.