Managing log files with logrotate
Log Rolling
Regularly switching log files keeps them from filling up the filesystem, but the logrotate tool can do much more.
Linux log files do not take up much space. Even with systemd, many logs continue to be text files. All the same, if left unattended, log files would eventually fill their entire filesystem – and, if that filesystem is root, crash the system. To avoid this eventuality, Linux uses logrotate, a system of multiple logs that are switched regularly, either at a specified time or when the file size reaches the designated limit.
Logrotate is installed by default in every distribution of which I am aware. You can usually take for granted that logrotate is installed, but you can check by running the command ls /var/log. If you see multiple files with numbered suffixes, then logrotate is installed. Alternatively, in some distributions, you can run less /var/lib/logrotate.status to see the latest logrotate activity.
In fact, logrotate is required by a Linux system, because many standard applications use logs by default, including apache, aptitude, cups-daemon, and dpkg. Ordinarily, such logs exist as much for the system as the administrator, but they can be invaluable for troubleshooting. You may want to modify the default setups for a log or rotate a log for your own scripts.
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