SSH Port Forwarding

ssh-port-forwarding.sh

#!/bin/bash
 
HOSTNAME=YOUR_HOST_NAME
USERNAME=YOUR_USER_NAME
 
if [ $# -lt 1 ]
then
    echo "Usage: $0 PORT [TARGET_PORT]"
    exit 1
fi
 
port=$1
target_port=$2
if [ "x$target_port" == "x" ]
then
    target_port=$port
fi
 
 
m=$port:localhost:$target_port
_pid=""
 
function getPid() {
    _pid=`ps -o pid,command -e | grep "$m" | grep -v grep | awk '{print $1}'`
}
 
getPid
 
if [ "x$_pid" != "x" ]
then
    echo "Kill existing process: $_pid..."
    kill $_pid
    if [ $? -ne 0 ]
    then
        echo "Error: failed to kill $_pid"
        exit 1
    fi
fi
 
ssh -L$m $USERNAME@$HOSTNAME -f -N
 
if [ $? -ne 0 ]
then
    echo "Error: failed to start port forwarding $port"
    exit 2
fi
 
sleep 3
_pid=""
 
getPid
 
if [ "x$_pid" == "x" ]
then
    echo "Error: failed to start port forwarding $port(2)"
    exit 3
fi
 
echo "Started, pid: $_pid"