Homebrew install specific version of formula?

Question

How do I install a specific version of a formula in homebrew? For example, postgresql-8.4.4 instead of the latest 9.0.

Answer 1

Upgraded Postgres by accident?

My case:

• postgresql was upgraded from 11 to 12 accidentally (after running brew upgrade without arguments)
• I want to keep Postgres 11.

Solution:

1. Stop the DB:

brew services stop postgresql

2. Install Postgres 11:

brew install postgresql@11

3. Enable it:

brew link postgresql@11 --force

4. (Optional) Rename DB data directory from postgres to postgres@11:

cd /usr/local/var
ls -lh
mv postgresql@11 postgresql@11-fresh-backup
mv postgres postgresql@11

5. Start the DB:

brew services start postgresql@11

If you have any errors, check /usr/local/var/log/postgresql@11.log (notice the @11).