A nice way of parsing options passed to a bash script without relying on position: 

#!/bin/bash

for i in "$@"
  do
    case $i in

      --node-port=*)
      NODEPORT="${i#*=}"
      ;;
 
      --jjp-host=*)
      JJPHOST="${i#*=}"
      ;;
 
      --jjp-port=*)
      JJPPORT="${i#*=}"
      ;;
 
      --spp-host=*)
      SPPHOST="${i#*=}"
      ;;
 
      --spp-port=*)
      SPPPORT="${i#*=}"
      ;;

      --help)
      echo ""
      echo "Usage example: start_app --spp-host=jupiter --spp-port=2000  --node-port=3000 --jjp-host=neptune --jjp-port=4000"
      echo ""
      ;;

 
      *)
      ;;
  
  esac
done
 
[ "${NODEPORT}XXX" == "XXX" ] && { echo "Warning: NODEPORT env var not set"; }
[ "${JJPHOST}XXX" == "XXX" ] && { echo "Warning: JJPHOST env var not set"; }
[ "${JJPPORT}XXX" == "XXX" ] && { echo "Warning: JJPPORT env var not set"; }
[ "${SPPHOST}XXX" == "XXX" ] && { echo "Warning: SPPHOST env var not set"; }
[ "${SPPPORT}XXX" == "XXX" ] && { echo "Warning: SPPPORT env var not set"; }
 
export NODEPORT
export JJPHOST
export JJPPORT
export SPPHOST
export SPPPORT
 
cd /applications/my_app
nohup npm run start &