cheat-sheet-linux-ssh.md

SSH

Check Existing SSH Keys

ls -al ~/.ssh

If you receive an error indicating that ~/.ssh does not exist, you do not have an SSH key pair at the default location.

Generate a New SSH Key

ssh-keygen -t ed25519 -C "your_email@example.com"

If you are using a legacy system that does not support the Ed25519 algorithm, use:

ssh-keygen -t rsa -b 4096 -C "your_email@example.com"

Add Your SSH Key to the SSH Agent

Start the SSH agent in the background.

eval "$(ssh-agent -s)"

Add your SSH private key to the SSH agent.

ssh-add ~/.ssh/<ssh_key>

Remove a Remote Host from the "known_hosts" File

ssh-keygen -f ~/.ssh/known_hosts -R <ip>

Copy SSH Key to Remote Host

ssh-copy-id <user>@<host>

Connect to a Remote Host

ssh <user>@<host>

SSH Tunnel (Port Forwarding)

Local Port Forwarding

ssh -L <local_port>:<remote_host>:<remote_port> <user>@<host>

Remote Port Forwarding

ssh -R <remote_port>:<local_host>:<local_port> <user>@<host>

Execute a Command on a Remote Host

ssh <user>@<host> '<command>'

Check SSH Connection

ssh -T <user>@<host>