Install linux

If you want to upgrade 16.04 to 18.04, you can follow the steps below.

Upgrade Ubuntu 16.04 LTS To Ubuntu 18.04 LTS Server

Removing unwanted kernels

$ uname -r → lists current kernel

$ sudo dpkg --list 'linux-image*'|awk '{ if ($1=="ii") print $2}'|grep -v `uname -r` → List the old kernel

Info about operating system

uname -m (architecture of the system) -a (full info)