Errr 'mongo.js:L112 Error: couldn't connect to server 127.0.0.1:27017 at src/mongo/shell/mongo.js:L112'

If you are running Ubuntu, then there is an issue with folder ownership.  Run these commands: Stop the MongoDB service ------------------------------------------------------------------------------------------------------------------------------- sudo service mongodb stop ------------------------------------------------------------------------------------------- Remove the MongoDB lock file -------------------------------------------------------------------------------------------------------------------------------  sudo rm /var/lib/mongodb/mongod.lock -------------------------------------------------------------------------------------------- Change ownership from root to the MongoDB path -------------------------------------------------------------------------------------------------------------------------------  sudo chown -R mongodb:mongodb /var/lib/mongodb/ --------------------------------------------------------------------------------------------- Start the MongoDB service -------------------------------------------------------------------------------------------------------------------------------  sudo service mongodb start ---------------------------------------------------------------------------------------------- Test the mongo application -------------------------------------------------------------------------------------------------------------------------------  mongo  ---------------------------------------------------------------------------------------------