Check app name exist, or not in PM2 (JS)

pm2_check_app_name.sh

#!/bin/bash
# Set App name
APP_NAME=node_server

# Get information by app name with pm2
pm2 describe $APP_NAME > /dev/null

# Save data of previous shell to here
IS_EXIST_BY_APP_NAME=$?

if [ "${IS_EXIST_BY_APP_NAME}" -ne 0 ]; then
  pm2 start [do the write thing] --name=$APP_NAME
else
  pm2 restart $APP_NAME
fi;