General Commands for Linux

Ubuntu Openssh Server Install

sudo apt install openssh-server -y

Create a new user on Ubuntu

adduser name_of_the_user
usermod -aG sudo name_of_the_user #if required to elevate user to sudo group

Generate SSH Key to login to Server

• From the control node generate the SSH Keygen using 4096 bit

ssh-keygen -t ed25519 -C "NAME_OF_THE_CONTROL_NODE"
    \\ save it to the default location but with the name of the host_node_key
    \\ use a passphrase for added authentication
    \\ copy the public key to the host node
ssh-copy-id -i LOCATION_OF_THE_PUBLIC_KEY_WITH_NAME username@IP_ADDRESS_HOST_NODE
    \\ To login to specifc server using a specific key
ssh -i LOCATION_OF_THE_PRIVATE_KEY username@IP_ADDRESS_HOST_NODE

• Connecting to Linux Terminal from Windows using Putty https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/putty.html

• Find out the DNS servers for a linux machine

resolvectl status

• Change Permission ownership of a folder / file to the current user

sudo chown -R $USER:$USER folder_name_location