Simple init script for creating an ssh tunnel

ssh-tunnel-init.rb

#!/usr/bin/env ruby
#Init script for setting up a ssh tunnel

#Remote Port
tun_port     = 123
#Local port to use
tun_lport    = 1234
#Remote User
tun_user     = 'username'
#Remote Host
tun_host     = '1.2.3,4'

tun_pid_file = '/tmp/tunnel.pid'

tun_pid, proc_ps_info = nil, nil
if File.exists?(tun_pid_file)
  tun_pid = File.read(tun_pid_file).chomp
  tun_pid = tun_pid.to_i
  proc_ps_info = `ps aux | awk '$2 == #{tun_pid} {print $_}'`
end

def kill_pid(pid,signal)
  if pid
    puts "Killing PID #{pid}"
    `kill -#{signal} #{pid}`
  else
    puts "Cannot stop tunnel, no known/running process."
  end
end

case ARGV[0]
  when 'stop'
    kill_pid(tun_pid,15)
  when 'force-stop'
    kill_pid(tun_pid,9)
  when 'status'
    unless proc_ps_info.nil? || proc_ps_info.empty?
      puts proc_ps_info
    else
      puts "Cannot show status. No known/running process"
    end
  when 'start','restart'
    unless proc_ps_info.nil? || proc_ps_info.empty?
      puts "Found a running tunnel... sending SIGTERM efore starting"
      kill_pid(tun_pid,15)
    end
    cmd="ssh -N -L #{tun_lport}:#{tun_host}:#{tun_port} #{tun_host} -l #{tun_user}"
    pid = Process.fork do
      exec(cmd)
    end
    puts "Started a new tunnel with PID #{pid}"
    File.open(tun_pid_file,'w') {|f| f.write pid.to_s}
  else
    puts "Unrecognized/no option, try (start|restart|status|stop|force-stop)"
end