ryukinix

(defun executables ()
  (loop with path = (uiop:getenv "PATH")
        for p in (uiop:split-string path :separator ":")
        for dir = (probe-file p)
        when (uiop:directory-exists-p dir)
          append (uiop:directory-files dir)))

(defun find-executable (name)
  (find name (executables)
        :test #'equalp