How do you restart logstash on an AWS server?

This is a pretty basic question, but I coiuld nto for the life of me find a straight answer about it on google.

I have logstash/Kibana/Elastisearch installed and working on an AWS server. Due to some complications, logstash stopped sending files to Kibana, and I wanted to restart it to see if it would fix the issue. (This is on an Ubuntu 14.04.2).

All of the commands I looked up on google would not restart the service properly. If I check the services running, logstash is on that list and has a -.

restart logstash gives the error "Unknown job: logstash", and some of the others I found gave a similar kind of error.

What is the proper command to run in order to restart logstash?