[LINUX] Manage logrotate generations with a shell script.

If you want to keep 3 generations, you can use the script one liner below. (The idea is to leave 3 generations → read as deleting all files other than the 3 generations you want to keep)

(When erasing from the oldest one in time) ls -1rt | head -n -3 | xargs rm -rf

(When deleting the oldest date such as testlog20200701) ls -1 | head -n -3 | xargs rm -rf

Description (when erasing the old one judging from the character string in the log)

1. Place a dummy log

touch testlog2020070{1..9}

2. Confirmation

ls -la

-rw-r--r--. 1 root root 0 May 17 16:40 testlog20200701 -rw-r--r--. 1 root root 0 May 17 16:40 testlog20200702 -rw-r--r--. 1 root root 0 May 17 16:40 testlog20200703 -rw-r--r--. 1 root root 0 May 17 16:40 testlog20200704 -rw-r--r--. 1 root root 0 May 17 16:40 testlog20200705 -rw-r--r--. 1 root root 0 May 17 16:40 testlog20200706 -rw-r--r--. 1 root root 0 May 17 16:40 testlog20200707 -rw-r--r--. 1 root root 0 May 17 16:40 testlog20200708 -rw-r--r--. 1 root root 0 May 17 16:40 testlog20200709

3. Extraction of deletion target I want to keep 20200707 to 20200709 → (read as I want to delete testlog 20200701 to 20200706)

ls -1 | head -n -3

testlog20200701 testlog20200702 testlog20200703 testlog20200704 testlog20200705 testlog20200706

4. Delete the extracted log

ls -1 | head -n -3 | xargs rm -rf

Verification

ls -la

testlog20200707 testlog20200708 testlog20200709

I was able to leave the desired 3 generations.

*) (When erasing from the oldest one in time) is realized by performing with ls -1rt. Option t Sort by time Option r Sort in reverse

It is assumed that the log rotation itself is performed using the Linux standard logrotate.d, and only the deleted part is performed by the shell script. (Because the deletion script of logrotate.d is processed in the form of x days ago, if the deletion script does not work for some reason, the log may remain)