Secure shell (ssh)
ssh allows you to have terminal access to a linux computer.
Install open ssh server on the computer you want to remote onto (the host):
sudo apt-get openssh-server
The ssh client installed as standard on most Linux distrubutions:
Run shh client on the client computer:
ssh user_id@ip_address_of_host
On a client computer running Windows, install the free PuTTY application and use this instead of ssh.
On a Kindle Fire, install the free Serverauditor SSH/SFTP client app instead of ssh.