接着上次 磁盘满了 需要清理系统盘
1，先用uname -a 查看当前内核版本:
uname -a
Linux 10-9-37-135 3.13.0-110-generic #157-Ubuntu SMP Mon Feb 20 11:54:05 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
版本是3.13.0-110
2，看一下当前系统安装的内核版本:
dpkg --get-selections|grep linux
libselinux1:amd64 install
linux-firmware install
linux-generic install
linux-headers-3.13.0-100 install
linux-headers-3.13.0-100-generic install
linux-headers-3.13.0-101 install
linux-headers-3.13.0-101-generic install
linux-headers-3.13.0-103 install
linux-headers-3.13.0-103-generic install
linux-headers-3.13.0-105 install
linux-headers-3.13.0-105-generic install
linux-headers-3.13.0-106 install
linux-headers-3.13.0-106-generic install
linux-headers-3.13.0-107 install
linux-headers-3.13.0-107-generic install
linux-headers-3.13.0-108 install
linux-headers-3.13.0-108-generic install
linux-headers-3.13.0-109 install
linux-headers-3.13.0-109-generic install
linux-headers-3.13.0-110 install
linux-headers-3.13.0-110-generic install
linux-headers-3.13.0-63 install
linux-headers-3.13.0-63-generic install
linux-headers-3.13.0-68 install
linux-headers-3.13.0-68-generic install
linux-headers-3.13.0-71 install
linux-headers-3.13.0-71-generic install
linux-headers-3.13.0-74 install
linux-headers-3.13.0-74-generic install
linux-headers-3.13.0-76 install
linux-headers-3.13.0-76-generic install
linux-headers-3.13.0-77 install
linux-image-3.13.0-100-generic install
linux-image-3.13.0-101-generic install
linux-image-3.13.0-103-generic install
linux-image-3.13.0-105-generic install
linux-image-3.13.0-106-generic install
linux-image-3.13.0-107-generic install
linux-image-3.13.0-108-generic install
linux-image-3.13.0-109-generic install
linux-image-3.13.0-110-generic install
linux-image-3.13.0-24-generic deinstall
linux-image-3.13.0-63-generic install
linux-image-3.13.0-68-generic install
linux-image-3.13.0-71-generic install
linux-image-3.13.0-74-generic install
linux-image-3.13.0-76-generic install
linux-image-3.13.0-77-generic install
linux-image-extra-3.13.0-100-generic install
linux-image-extra-3.13.0-101-generic install
linux-image-extra-3.13.0-103-generic install
linux-image-extra-3.13.0-105-generic install
linux-image-extra-3.13.0-106-generic install
linux-image-extra-3.13.0-107-generic install
linux-image-extra-3.13.0-108-generic install
linux-image-extra-3.13.0-109-generic install
linux-image-extra-3.13.0-110-generic install
linux-image-extra-3.13.0-24-generic deinstall
linux-image-extra-3.13.0-63-generic install
linux-image-extra-3.13.0-68-generic install
linux-image-extra-3.13.0-71-generic install
linux-image-extra-3.13.0-74-generic install
linux-image-extra-3.13.0-76-generic install
linux-image-extra-3.13.0-77-generic install
linux-image-generic install
linux-libc-dev:amd64 install
pptp-linux install
util-linux install
太惊人了 竟然这么多 主要是年头长，然后把不需要的都删除就行
3，删除多余的内核
上面linux-headers、linux-image、linux-signed开头的都是跟内核相关的.带有版本号的(如linux-image-extra-3.13.0-63-generic)才是可以删除的.注意不要删除当前使用的版本.
sudo apt-get purge来删除
sudo apt-get purge linux-image-extra-3.13.0-63-generic
sudo apt-get purge linux-signed-image-3.13.0-63-generic
sudo apt-get purge linux-headers-3.13.0-63(这个会自动把linux-headers-3.13.0-63-generic删除)
注意
不要使用sudo apt-get remove来删除,会出现linux-signed-image-3.13.0-63-generic deinstall
4，使用sudo update-grub更新启动菜单
小结
内核占用系统盘内存比较大 /usr/src 虽然只有2.5G 但是实际清理完会有7个多G