I was in the habit of switching from my Emacs session to the command line to run git grep, which my brother had seen a couple times, and recommended the Silver Searcher (Ag) search utility.

The initial install was straightforward via MacPorts:

port install the_silver_searcher

But setting up in Emacs took a couple more steps than I anticipated, so I’ve outlined some tips here.

First, I needed MELPA setup as a Emacs package archive, so I had to add this to my .emacs file:

;; Add MELPA as a resource for emacs packages.
(require 'package)
(add-to-list 'package-archives '("melpa" . "https://melpa.org/packages/") t)

Then the ag package was easy enough to find (search for “silver”).

Secondly, I needed to load exec-path-from-shell into my .emacs file as well:

;; Load exec-path-from-shell
(when (memq window-system '(mac ns))

Only after this was I able to start running commands like M-x ag-project from within Emacs.