Which version of Linux am I running and how do I upgrade?

Version of Linux kernel:

uname -a

32 or 64 bit:

uname -m

What distro and version you’re running:

cat /etc/*release
cat /etc/issue
lsb_release -a

Upgrade CentOS:

yum list updates
yum update

Upgrade Ubuntu:

sudo apt-get update
sudo apt-get install update-manager-core

Edit the last line of this file accordingly:

vi /etc/update-manager/release-upgrades

Then it’s time to upgrade:

sudo do-release-upgrade