Collection of useful SSH commands

Create cryptographically strong SSH key

Create a new pair of public and private SSH keys

ssh-keygen

Next open up your public SSH key and change the last section to a memorable name. The last part is treated as a comment.

code ~/.ssh/id_rsa.pub

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Copy SSH key to a server

Copy your public SSH key to a remote server for authentication

ssh-copy-id root@<ip-address>

Next enter the password for the account that you are adding SSH authentication to. After this you should be able to authenticate to the server without providing a password.

SSH into a remote machine

ssh -p <port-number> -i <path-to-ssh-keys> root@<ip-address>

Running a one off command on the remote machine

ssh root@<ip-address> hostname

SSH config

Simplify connections with SSH config files

Add ~/.ssh/config file

Host foo
    HostName 127.0.0.1
    User root
    IdentityFile ~/.ssh/id_rsa
    Port 22

Now you can SSH with ssh foo and that will use your configured values.