Centos 6.3 delete old Kernel

Centos 6.3 often updates the kernel, resulting in many startup items added during startup. we can delete the old kernel and keep the latest kernel to release some disk space.

(1) view installed kernels

command: rpm-Q kernel
display result: kernel-2.6.32-279.el6.i686
kernel-2.6.32-279.9.1.el6.i686
kernel-2.6.32-279.11.1.el6.i686
kernel-2.6.32-279.14.1.el6.i686
(2) Delete old kernel

Install Yum-UTLS: sudo install Yum-utils

Set how many old kernels you want to retain, for example, I want to keep two: sudo package-cleanup -- oldkernels -- count = 2

Run the rpm-Q kernel command again to view the kernel information. There are only two latest kernel information:
Kernel-2.6.32-279.11.1.el6.i686
Kernel-2.6.32-279.14.1.el6.i686

(3) set the number of permanent kernel installations. I have set two

Sudo gedit/etc/yum. conf

Set installonly_limit = 2

(4) restart and you will only see two kernel boot items.