I’m on Ubuntu 18.04 having PostgreSQL 10.10 installed. For testing I had to run PostgreSQL 9.5 along with 10.10.
If you don’t know how to install version 9 on Ubuntu 18.04 check this doc on postgres site.
To install version 9.5 just run:
sudo apt install postgresql-9.5
That’s it. You should not face any other issues.
I’ve been always starting postgres instance with sudo service postgresql start but now,
when we have two different version we should use: