我正在管理几台用于核心服务（NTP、DNS 等）的服务器，我突然发现其中一台服务器似乎保留了 3 个最新内核，而不是其他服务器上的 2 个：
nul@quark:~$ sudo apt-get autoremove --purge
Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
nul@quark:~$ dpkg -l |grep linux-image
ii linux-image-3.13.0-51-generic 3.13.0-51.84 amd64 Linux kernel image for version 3.13.0 on 64 bit x86 SMP
ii linux-image-3.13.0-52-generic 3.13.0-52.85 amd64 Linux kernel image for version 3.13.0 on 64 bit x86 SMP
ii linux-image-3.16.0-37-generic 3.16.0-37.49~14.04.1 amd64 Linux kernel image for version 3.16.0 on …