Open Source Software Shortcut — Escaping SSH With ‘~’

“One thing you may not know about SSH is that it has an escape
character: ~. To try it out, hit return (the escape character is
only picked up at he start of a line, so you must make sure you
are) at the console in an active SSH session, then enter ~. Nothing
will show on screen; so far so good. Next, hit Ctrl-Z and the
session will be suspended — handy if you want to check something
on your local box without logging all the way out of SSH. This
trick will also work from within screen, and even from within mutt.
To return to your SSH session, type fg and hit return.”

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