Postgres
From Steak Wiki
Backup / Restore DB
This will run the dump as the postgres user via su, and avoids some of the permissions errors that can creep up.
# cd /tmp (just need a writeable directory, aka 777) # su -c 'pg_dump mydb >> mydb_dump_2020.sql' postgres
assuming you have a postgres admin user, with all rights, this will backup the db. If you are remote, you might need something similar to (localhost/ip, ports, etc specified):
pg_dump -U username -h localhost databasename >> sqlfile.sql
ref: https://stackoverflow.com/questions/37984733/postgresql-database-export-to-sql-file
Create a user
Note that if you have an existing db, you might want to add ownership to this user, or r/w permissions.