Here are my most used commands in Linux. Current favoured distibution is Ubuntu Server 16.04.3 LTS (Xenial Xerus).

# apt-get is the lower level, apt is meant to be more pleasant!

sudo apt update        # updates packages
sudo apt --upgradeable  # shows list
sudo apt upgrade        # does the upgrade


apt-get update    # updates the package lists
apt-get upgrade   # upgrades current packages
apt-get dist-upgrade  # distribution updates

apt-get install openssh-server  # so can ssh, and scp into the machine

# copy to the linux machine
scp * dave@xps:wordpress/.
scp docker-compose.yml uploads.ini wp-config.php dave@xps:wordpress/.

# copy from the linux machine
-p preserving date
-r recurse
scp -rp azureuser@testmachine.westeurope.cloudapp.azure.com:/var/log/apache2/* .

top
df -h  # check disk usage

tar cc
tar xvf

pwd
ls -lat
ps -ef
kill -9 1234

rm -rf *
chmod -777 *

cat /proc/version
uname -a
lsb_release -a

sudo adduser bob

reboot now  
sudo su

Azure CLI

One line from MS Docs to install AzureCLI and Drupal and AzureCLI.

If you come across file lock issues - debconf dbdriver config dat is locked by another process, try this link which tells you to find the process then kill it.

sudo fuser -v /var/cache/debconf/config.dat
kill PID

Tools

# A nice verison of top showing all processors
sudo apt-get install htop
sudo apt-get install iotop
sudo iotop

Installing Dot Net Core

Microsoft

Installing Ubuntu Server

https://www.ubuntu.com/download/server

Install instructions using Rufus to create a bootable USB stick.