1. Install Postgres

   brew install Postgres
   

2. Try to log in.

   $ psql -h localhost -d postgres -U postgres  
   psql: error: could not connect to server: 
   FATAL:  role "postgres" does not exist
   

3. Create the user

    $ /usr/local/opt/postgres/bin/createuser -s postgres 
   

4. Start the server

   $ pg_ctl -D /usr/local/var/postgres start 
   pg_ctl: another server might be running; trying to start server anyway
   waiting for server to start....2020-06-27 18:12:07.784 +08 [20812]
    FATAL:  lock file "postmaster.pid" already exists
   2020-06-27 18:12:07.784 +08 [20812] HINT:  Is another postmaster (PID 4901)
    running in data directory "/usr/local/var/postgres"?
    stopped waiting
   pg_ctl: could not start server
   Examine the log output.
   

It just works!!

$ psql -h localhost -d postgres -U postgres
psql (12.3)
Type "help" for help.

postgres=#

References

• https://stackoverflow.com/questions/15301826/psql-fatal-role-postgres-does-not-exist
• https://stackoverflow.com/a/35308200/1357375

Written with StackEdit.