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ssh

Secure shell for remote login and tunneling.

Basics​

  • Connect with key
ssh -i ~/.ssh/id_ed25519 user@host
  • Specify port and command
ssh -p 2222 user@host 'uname -a'

Key management​

  • Generate key
ssh-keygen -t ed25519 -C "you@example.com"
  • Copy public key to server
ssh-copy-id -i ~/.ssh/id_ed25519.pub user@host

Config file (~/.ssh/config)​

Host mybox
	HostName example.com
	User ubuntu
	Port 22
	IdentityFile ~/.ssh/id_ed25519
	ForwardAgent yes
  • Use it
ssh mybox

Tunnels​

  • Local port forward (access remote service locally)
ssh -L 5433:localhost:5432 user@db-host
  • Remote port forward (expose local to remote)
ssh -R 8080:localhost:3000 user@host
  • Dynamic SOCKS proxy
ssh -D 1080 user@host

Multiplexing (faster repeated SSH)​

Host *
	ControlMaster auto
	ControlPath ~/.ssh/cm-%r@%h:%p
	ControlPersist 10m

Common options​

  • -o StrictHostKeyChecking=no # auto-accept host key (use with caution)
  • -A ForwardAgent # agent forwarding
  • -J jump-host # ProxyJump

SCP and SFTP​

  • Copy files
scp file user@host:/path/
  • SFTP session
sftp user@host