Remove all old installed but unused kernels

I just noticed I had 8 kernels installed on a machine. dont need but one…. so I rebooted to make sure I was using the newest, and removed all the old ones via these simple commands :   Ubuntu / Debian / dpkg / Apt: dpkg -l ‘linux-*’ | sed ‘/^ii/!d;/'”$(uname -r | sed “s/\(.*\)-\([^0-9]\+\)/\1/”)”‘/d;s/^[^ ]* [^ ]* \([^ ]*\).*/\1/;/[0-9]/!d’ | xargs sudo apt-get -y purge Thats a one liner, so just copy paste the whole thing. Centos / RHEL / Yum / RPM: uname -r See which kernel is being used. rpm -q kernel get a list of installed kernels yum install yum-utils make sure yum-utils is installed package-cleanup –oldkernels –count=1 Cleanup old packages, the count can be any number and it will keep that number of the latest packages. count 2 will keep the current newest and one more, 3 will keep the current newest and 2 more and so on. nano yum.conf edit /etc/yum.conf and look forĀ installonly_limitĀ and change it to any number, this was the kernels will be cleaned up automatically. I have mine set to 3. installonly_limit=3