A quick piece of code to read .env files. A line beginning with a # is treated as a comment. When this grows, I plan to make a separate project and push into quicklisp.

read-dot-env.lisp

(defun load-env (pathname)
  (with-open-file (stream pathname)
    (read-env stream)))

(defun read-env (stream)
  (remove-nils
   (loop for line = (read-line stream  nil :eof)
      until (eq line :eof)
      collect (process-env-string line))))

(defun remove-nils (env-param-list)
  (loop for env-param in env-param-list
     if env-param
     collect env-param))

(defun process-env-string (env-string)
  (if (not (equalp (char env-string 0) #\#))
      (split-string env-string)))

(defun split-string (env-string)
  (let ((pos (position #\= env-string :test #'equal)))
    (list (subseq env-string 0 pos) (subseq env-string (+ pos 1)))))

; run as follows
(load-env ".env")