Are you using docker now? If so the database will be stored inside your postgres container. You can find the ID for the container by running:
sudo docker ps
Once you know the ID you can run the commands suggested by @SISalp in the container by doing something like this: (remember to change the [container_id] for the one you previously found)
sudo docker exec [container_id] pg_dump -U tryton -O tryton >backup.sql
and
sudo docker exec [container_id] psql -U tryton -d tryton <backup.sql
More information on postgres backup and restore can be found in their documentation.
If you are not using docker then you should be able to use the commands above without the “sudo docker exec [container_id]” part, although the user name and database name may be different.