Remove old kernels on Linux

Display current kernel

  $ uname -r
  $ uname -mrs

On ubuntu

• List all installed kernels

  $ dpkg --list | grep linux-image
  

• Remove old kernels

  $ sudo apt-get autoremove
  

On RedHat, CentOS, and Fedora

• list all installed kernels

  $ rpm -qa kernel
  

• Remove old kernels

  # install yum utils
  $ dnf install yum-utils
  $ yum install yum-utils
  # Package-cleanup set count as how many old kernels you want left 
  $ package-cleanup --oldkernels --count=2
  

• Make amount of installed kernels permanent
  Edit /etc/yum.conf or /etc/dnf/dnf.conf and set installonly_limit:

  installonly_limit=2
  

Written on April 27, 2017