一行移除全部舊的kernel image

先

sudo apt-get purge $( dpkg --list | grep -P -o "linux-image-\d\S+" | grep -v $(uname -r | grep -P -o ".+\d") )

然後

sudo update-grub2

執行grub的更新

備註：如果是剛更新完成請先重開機

ref: http://askubuntu.com/questions/176322/removing-old-kernel-entries-in-grub