Add Tell direnv To Load The Env File as a Unix TIL

Author: jbranchaud

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).
 
-_1387 TILs and counting..._
+_1388 TILs and counting..._
 
 ---
 
@@ -1406,6 +1406,7 @@ _1387 TILs and counting..._
 - [Specify The Language For A File With Bat](unix/specify-the-language-for-a-file-with-bat.md)
 - [Sort In Numerical Order](unix/sort-in-numerical-order.md)
 - [Switch Versions of a Brew Formula](unix/switch-versions-of-a-brew-formula.md)
+- [Tell direnv To Load The Env File](unix/tell-direnv-to-load-the-env-file.md)
 - [Touch Access And Modify Times Individually](unix/touch-access-and-modify-times-individually.md)
 - [Undo Some Command Line Editing](unix/undo-some-command-line-editing.md)
 - [Update Package Versions Known By asdf Plugin](unix/update-package-versions-known-by-asdf-plugin.md)

unix/tell-direnv-to-load-the-env-file.md

@@ -0,0 +1,22 @@
+# Tell direnv To Load The Env File
+
+By default [`direnv`](https://direnv.net/) looks for and evaluates the `.envrc`
+file that appears in a given project directory. This default behavior is good
+for things like setting certain path dependencies (e.g. a specific version of
+node or postgres).
+
+To the end of using `direnv` to set up the development environment, it can be
+useful to have it also load the `.env` file into the current shell's
+environment.
+
+To get `direnv` to do that, add this line to the `.envrc` file:
+
+```
+dotenv_if_exists .env
+```
+
+This specific loads all the environment variables in `.env`. If there are other
+files, such as `.env.development` that need to be loaded in, those can be
+included with additional
+[`dotenv_if_exists`](https://direnv.net/man/direnv-stdlib.1.html#codedotenvifexists-ltdotenvpathgtcode)
+declarations.