参考博客：https://www.cnblogs.com/ssyfj/p/16278883.html
1、系统版本查看
查看ubuntu版本号
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 18.04.6 LTS
Release: 18.04
Codename: bionic
查看内核版本号
$ uname -sr
Linux 5.4.0-124-generic
查看曾经安装的内核版本号
$ sudo dpkg --get-selections | grep linux-image
linux-image-5.4.0-124-generic install
linux-image-5.4.0-84-generic install
linux-image-generic-hwe-18.04 install
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