#check-ssh-tunnel.sh
COMMAND="/usr/bin/screen -dmS ssh-Ubuntu /usr/bin/ssh -R 2255:localhost:22 user@domain-Desktop-Ubuntu.com -g"
COMMAND_SSH="/usr/bin/ssh -R 2255:localhost:22 domain-Desktop-Ubuntu.com -g"
PID=$(/usr/bin/pgrep -f -x "$COMMAND_SSH")
if [ "$PID" = "" ]
then
    $COMMAND
fi

ssh -p 2255 pi@localhost