Create ssh tunnel in shell script

tunnel.sh

remoteHost=xxx.xxx.xxx.xxx
remoteUser=uuuuuuuu
remotePort=XXXX
localPort=YYYY

function cleanup() {
  ssh -S my-ctrl-socket -O exit ${remoteUser}@${remoteHost}
}

trap cleanup EXIT SIGHUP SIGINT SIGQUIT SIGABRT

# Create database tunnel.
ssh -S my-ctrl-socket -O exit ${remoteUser}@${remoteHost} >/dev/null 2>&1
ssh -4 -o ServerAliveInterval=5 -o ServerAliveCountMax=3 -M -S my-ctrl-socket -fnNT -L ${localPort}:localhost:{$remotePort} ${remoteUser}@${remoteHost} || exit $?
ssh -S my-ctrl-socket -O check ${remoteUser}@${remoteHost}