PostgreSQL

Login to Postgres

# [email protected]:~ #
su - postgres
# Last login: Mon Apr 16 10:26:05 MYT 2018 on pts/0
# -bash-4.2$
psql
# psql (9.6.8)
# Type "help" for help.
# 
# postgres=#

Login Error

# [email protected]:~ #
su - postgres psql
# Last login: Mon Apr 16 10:25:10 MYT 2018 on pts/0
# /bin/createuser: /bin/createuser: cannot execute binary file

Creating User

# [email protected]:~ #
su - postgres
# Last login: Mon Apr 16 10:26:05 MYT 2018 on pts/0
# -bash-4.2$
createuser root
# createuser: creation of new role failed: ERROR:  role "root" already exists

Creating Database

# [email protected]:~ #
su - postgres
# Last login: Mon Apr 16 10:26:05 MYT 2018 on pts/0
# -bash-4.2$
createdb root

Grant Privileges

# postgres=#
grant all privileges on database root to root;
# GRANT
# postgres=#
grant all privileges on database postgres  to root;
# GRANT