~^z
^z
(read: ctrl-z) pauses the execution of the current foreground task. That doesn't work in an ssh session, because it is intercepted by the remote shell. ~^z
is a special escape character for this case, to pause the ssh session and drop you back to the local shell.~?
~
escape character must always follow a newline to be interpreted as special.man ssh
for more details, search for ESCAPE CHARACTERS