Remove old kernels in CentOS, RHEL and Fedora

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