See git gist with instructions here
Run this:
sudo -u postgres psql
OR
psql -U postgres
in your terminal to get into postgres
NB: If you're on a Mac and both of the commands above failed jump to the section about Mac below
postgres=#
Run
CREATE USER new_username;
Note: Replace new_username with the user you want to create, in your case that will be tom.
postgres=# CREATE USER new_username;
CREATE ROLE
Since you want that user to be able to create a DB, you need to alter the role to superuser
postgres=# ALTER USER new_username SUPERUSER CREATEDB;
ALTER ROLE
To confirm, everything was successful,
postgres=# \du
List of roles
Role name | Attributes | Member of
-----------+------------------------------------------------+-----------
new_username | Superuser, Create DB | {}
postgres | Superuser, Create role, Create DB, Replication | {}
root | Superuser, Create role, Create DB | {}
postgres=#
Update/Modification (For Mac):
I recently encountered a similar error on my Mac:
psql: FATAL: role "postgres" does not exist
This was because my installation was setup with a database superuser whose role name is the same as your login (short) name.
But some linux scripts assume the superuser has the traditional role name of postgres
How did I resolve this?
If you installed with homebrew
run:
/usr/local/opt/postgres/bin/createuser -s postgres
If you're using a specific version of postgres, say 10.5
then run:
/usr/local/Cellar/postgresql/10.5/bin/createuser -s postgres
OR:
/usr/local/Cellar/postgresql/10.5/bin/createuser -s new_username
OR:
/usr/local/opt/postgresql@11/bin/createuser -s postgres
If you installed with postgres.app
for Mac run:
/Applications/Postgres.app/Contents/Versions/10.5/bin/createuser -s postgres
P.S: replace 10.5 with your PostgreSQL version