Linux system log files are by default set to rotate. Depending on the age or size, a sequence of files moves back a step, the oldest being removed and a new one taking over as the current log file.

Log mining to the rescue. In the single-server days, it was easy to simply grep through a log file or two. But in today’s distributed computing environment, it can be very difficult to trace down ...

The older log files might also be compressed, particuarly if they tend to be very large files. So, you might see logfile.1.gz instead of logile.1. How logrotate works.