Q:

Exiting ssh -tt session

I am executing a script on a remote ssh host as follows:
ssh -tt $USER@somehost 'bash -s' < ./myscript.sh
Notice the pseudo tty -tt switch.
My problem is that after the script has finished running the ssh session is not ending.  Typing exit doesn't do anything either.  How do I make it exit?

A:

You are missing an exit statement.
I suspect the reason that the exit is necessary is becase when you force allocation of a pty, the pty is expecting the input to be a terminal... Reading EOF from a terminal doesn't mean 'there is never, ever any more data to come' the way it does for a pipe / file - it just means that there is 'currently no more input from the user' - hence the hang... it's waiting for further input.
This input script (myscript.sh) 'hangs':
echo "Hello World..."

This doesn't:
echo "Hello World..."
exit 0

