Add Manage Major Versions With Brew And Direnv as a Postgres TIL

README.md

@@ -10,7 +10,7 @@ pairing with smart people at Hashrocket.
 
 For a steady stream of TILs, [sign up for my newsletter](https://crafty-builder-6996.ck.page/e169c61186).
 
-_1369 TILs and counting..._
+_1370 TILs and counting..._
 
 ---
 
@@ -722,6 +722,7 @@ _1369 TILs and counting..._
 - [List Database Users](postgres/list-database-users.md)
 - [List Various Kinds Of Objects](postgres/list-various-kinds-of-objects.md)
 - [Lower Is Faster Than ilike](postgres/lower-is-faster-than-ilike.md)
+- [Manage Major Versions With Brew And Direnv](postgres/manage-major-versions-with-brew-and-direnv.md)
 - [Max Identifier Length Is 63 Bytes](postgres/max-identifier-length-is-63-bytes.md)
 - [Open Heroku Database In Postico From Terminal](postgres/open-heroku-database-in-postico-from-terminal.md)
 - [pg Prefix Is Reserved For System Schemas](postgres/pg-prefix-is-reserved-for-system-schemas.md)

postgres/manage-major-versions-with-brew-and-direnv.md

@@ -0,0 +1,40 @@
+# Manage Major Versions With Brew and Direnv
+
+I can install multiple major versions of PostgreSQL to my machine with `brew`
+with commands like the following:
+
+```bash
+$ brew install postgresql@14
+$ brew install postgresql@16
+$ # ...
+```
+
+I can then start and stop specific Postgres server versions using the `brew
+services start/stop` commands. Let's say 14 is running, but I want to switch to 16.
+
+```bash
+$ brew services stop postgresql@14
+$ brew services start postgresql@16
+```
+
+Then I can use [`direnv`](https://direnv.net/) to manage the Postgres client
+(bin directory) that gets used for certain projects. This way when I run a
+command like `pg_dump` or `psql` it will use the one associated with a specific
+major version of Postgres.
+
+Assuming I already have `direnv` installed, I can add a `.envrc` to my project
+with the following line:
+
+```
+PATH_add /usr/local/opt/postgresql@16/bin
+```
+
+And then tell my system that the changes to this file are allowed to be sourced
+by `direnv`:
+
+```bash
+$ direnv allow .
+```
+
+That's it. Now I have PostgreSQL 16 (client and server) ready to use for my
+current project.