How do I figure out how Postgres was installed on my Linux system? I'm using Postges 9.6 on Ubuntu Linux 16.  I'm trying to figure out how the Postgres server was installed so I can figure out a command to start and stop it.  It evidently isn't installed as a Linux service

[rails@server ~]$ sudo service postgresql status
Redirecting to /bin/systemctl status postgresql.service
Unit postgresql.service could not be found.


"which psql" reveals

[rails@server ~]$ which psql
/usr/bin/psql


I'm sort of at a loss for the next steps in figure out the command to start and stop it.
If you are simply looking to start and stop it, and a service or systemctl module doesn't exist on your machine, you can use pg_ctl to start and stop the Postgres server.  You will also need to have the path to the data directory handy (typically, the folder that contains postgresql.conf and pg_hba.conf), and pass that in along with the -D flag:

pg_ctl -D /path/to/data_dir start|stop

If no data directory exists, you will either need further assistance to help you get an existing database cluster up and running, or you can use initdb to create a new database cluster