open up postgres in shell using homebrew code example

Example 1: how-can-i-start-postgresql-server-on-mac-os-x

If you want to manually start and stop PostgreSQL (installed via Homebrew), the easiest way is:

brew services start postgresql

and

brew services stop postgresql

If you have a specific version, make sure to suffix the version. For example:

brew services start postgresql@10

Example 2: run postgres locally

$ pg_ctl -D /usr/local/var/postgres -l /usr/local/var/postgres/server.log start

Example 3: install postgresql 12.4 home brew

brew install postgresql