How to make a schedule to clean logs on Linux ?
09 May 2016In the software developing developed increasable logs, we should make a schedule to clean it. In Linux system , we have a simple way to do it. This article will introduce two commands which are installed on Linux. First is crontab , that is a command which service for you to make a schedule to do something. Second, tmpwatch is a command which cleans tmp directory . This article illustrates how to use those two commands to achieve our work.
This command makes the work cycle to do it. The cycler time use minute, hour, week, month, and year. You can use crontab command to archive your work, and also edit /etc/crontab to do it. To security issues, /etc/cron . allow use to allow who can use this command. Vice versa, /etc/cron.deny use to deny who cannot use it.
The crontab content
[nick1811@centos-6 ~]$ cat /etc/crontab
SHELL=/bin/bash
PATH=/sbin:/bin:/usr/sbin:/usr/bin
MAILTO=root
HOME=/
# For details see man 4 crontabs
# Example of job definition:
# .---------------- minute (0 - 59)
# | .------------- hour (0 - 23)
# | | .---------- day of month (1 - 31)
# | | | .------- month (1 - 12) OR jan,feb,mar,apr ...
# | | | | .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat
# | | | | |
# * * * * * user-name command to be executed
Temporary files are almost placed in /tmp directory, and be deleted by the system. To assurance the /tmp directory is not full, the system automatically cleans it in each day. This because the system makes a schedule to execute tmpwatch to do it. This package is not installed in minimum installation.
Using yum to install package :
[root@centos-6 ~]# yum install tmpwatch.x86_64
After installing, the tmpwatch file will be placed on this location( /etc/cron . daily). We can use cat to view it. All files in the /tmp will be deleted when it be not accessed in 30 days. This file shows the system recursively detects /tmp directory and deletes files.
[nick1811@centos-6 ~]$ cat /etc/cron.daily/tmpwatch
#! /bin/sh
flags=-umc
/usr/sbin/tmpwatch "$flags" -x /tmp/.X11-unix -x /tmp/.XIM-unix \
-x /tmp/.font-unix -x /tmp/.ICE-unix -x /tmp/.Test-unix \
-X '/tmp/hsperfdata_*' 10d /tmp
/usr/sbin/tmpwatch "$flags" 30d /var/tmp
for d in /var/{cache/man,catman}/{cat?,X11R6/cat?,local/cat?}; do
if [ -d "$d" ]; then
/usr/sbin/tmpwatch "$flags" -f 30d "$d"
fi
done
How to make a schedule to clean logs?
Now, we can make our schedule to clean logs. For an instance, we clean a directory at 1:30 in every day, and delete files which be not accessed in a month.
[nick1811@centos-6 ~]$ crontab -e
# Example of job definition:
# .---------------- minute (0 - 59)
# | .------------- hour (0 - 23)
# | | .---------- day of month (1 - 31)
# | | | .------- month (1 - 12) OR jan,feb,mar,apr ...
# | | | | .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat
# | | | | |
# * * * * * user-name command to be executed
30 1 * * * /usr/sbin/tmpwatch -maf 30d /home/nick1811/logs
