SSH

Create key

ssh-keygen -t ecdsa -b 521

# specif an file
ssh-keygen -t ecdsa -b 521 -f ~/.ssh/key-ecdsa

Copy public key

ssh-add ~/.ssh/id_ed25519
ssh-copy-id -i ~/.ssh/y-ecdsa.pub example_user@192.0.2.4

Add existing Key

ssh-add ~/.ssh/key-ecdsa

Alias

Host srv01
    HostName srv01.lan
    User john
    RemoteCommand cd ~/; exec bash --login
    RequestTTY yes

Port Binding

Bind local port 8001 to target-server port 80 using jump-machine.local.
(local machine without direct access to target-server)

ssh -f -N -L localhost:8001:target-server:80 usr@jump-machine.local