Your system to many old kernels version. How to remove old kernels in CentOS , RHEL and Fedora . For example, I have three kernel,and to keep two kernel on system. How to do it! To check kernel release on centos/RHEL and Fedora [huupv@huupv ~]$ uname -sr The output kernel release as below: Linux 4.15.15-300.fc27.x86_64 Checking installed kernel [huupv@huupv ~]$ rpm -q kernel The output three kernel as below: kernel-4.15.13-300.fc27.x86_64 kernel-4.15.14-300.fc27.x86_64 kernel-4.15.15-300.fc27.x86_64 Delete / Remove Old Kernels To install yum-utils [root@huupv huupv]# yum install yum-utils The output as below: Last metadata expiration check: 2:54:35 ago on Sat 14 Apr 2018 07:14:37 PM +07. Dependencies resolved. ================================================================================  Package                  Arch        Version                 Repository   Size ================================================================================ Installi

In this tutorial, How to install aide Centos. What does Aide mean AIDE is one of the most popular tools for monitoring the server changes in a LINUX based system.  It call as Advanced Intrusion Detection Environment. Install AIDE on Centos $ sudo yum install aide Check AIDE Version on your system $ sudo aide -v Configure AIDE $ sudo cp /etc/aide.conf /etc/aide.conf_BK Add lines not check /tmp and /proc in aide.conf file !/tmp !/proc Create the database $ sudo aide --init $ sudo mv /var/lib/aide/aide.db.new.gz /var/lib/aide/aide.db.gz $ sudo cd /var/lib/aide Run the AIDE check $ sudo aide --check Set cronjob to run AIDE check $ sudo vi /etc/cron.daily/aide // The content as below: #!/bin/bash MAILTO=root LOGFILE=/var/log/aide/aide.log AIDEDIR=/var/lib/aide /usr/sbin/aide  -u > $LOGFILE cp $AIDEDIR/aide.db.new.gz $AIDEDIR/aide.db.gz x=$(grep "Looks okay" $LOGFILE | wc -l) if [ $x -eq 1 ] then     echo "A