Specify type: -t rsa
Specify length: -b 4096
Specify filename: -f filename
ssh-keygen -t ed25519 -f filename
Forward port: -L 8888:localhost:8888
Only forward port, not execute command: -N
ssh -N -L 8888:localhost:8888 username@address -i identity_file_path
Modify file ~/.ssh/config
Host host_nickname
HostName 111.111.111.111
Port 8888
User username
IdentityFile path_to_private_key
LocalForward 8888 localhost:8888
ssh host_nickname