What is the meaning of "Do not execute a remote command"?

Usually, ssh will give you a remote shell by executing what is set up as your remote users login shell (e.g. /bin/bash). -N will prevent running anything, which is useful when you just want to use ssh to establish a connection and you don't need a remote shell.

e.g. forwarding ports or creating tunnels:

ssh -N -L 8080:127.0.0.1:80 user@server

And this is not only useful for forwarding ports.

E.g.: I use it in combination with -f and ControlMaster and ControlPath options (e.g. set up in .ssh/config), it can be used to create reusable connections.

ssh -fN user@server # creates a connection in the background that can be reused.

3 years ago