Log rotation in Linux systems

Using log rotation helps you manage your log files, so they don't keep growing indefinitely.

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This how-to is about rotating log files. Log rotation is useful for many reasons, but most importantly, it organizes logs by date instead of letting a single file grow indefinitely. Additionally, the rotated files are compressed and removed after a predetermined period.

Here you’ll find an example of how the logs can be rotated for a fictional application, myapp.

The following should be placed in /etc/logrotate.d/myapp.

/etc/logrotate.d/myapp

/home/myuser/log/myapp/*.log {
       weekly
       missingok
       notifempty
       rotate 20
       compress
       delaycompress
       create 640 myuser mygroup
}

In the example, we have an application named myapp that runs under the user myuser and group mygroup. The application writes its logs to the directory /home/myuser/log/myapp, producing two files there: info.log and error.log.

From top to bottom, we can see that:

• All log files are rotated weekly.

• Empty files are not rotated.

• If a file is missing, no error message is generated.

• Twenty weeks of history are retained.

• The rotated files are compressed.

• The most recently rotated file is left uncompressed.

• After rotation, a new empty file is created with permissions 640 and ownership myuser:mygroup.