find-grep-dired equivalents for ack and ag

Question

Is there an equivalent find-grep-dired using ack or ag? With the ability to specify the directory where the search starts? The Dired output itself is not so important (in fact I prefer the ack-mode result output). The closest thing I found is a Projectile ag/ack integration where the prefix argument prompts for the directory, but I was looking for something more general.

Answer 1

The ag package (available on MELPA) has the ability to run ag only within your specified folder or in project root. Check out its README on its github for more info.

Here are some of the answers from this stackexchange the elaborate on the use of ag in emacs:

• What is the easiest way to search all useful files inside a single project?
• Is there a way to use query-replace from grep/ack/ag output modes?

Answer 2

Here is small function that does what I was looking for; perhaps useful to someone else too. The function prompts for the directory and invokes the ag search-term. When invoked with the prefix argument the search-term is interpreted as regular expression.

(defun find-ag (dir search-term)
  "Run an ag search with SEARCH-TERM in the directory.

With an optional prefix argument ARG SEARCH-TERM is interpreted as a
regular expression."
  (interactive "DFind-ag (directory): \nsFind-ag (ag expression): ")
  (if (fboundp 'ag-regexp)
      (let ((ag-command (if current-prefix-arg 'ag-regexp 'ag))
            ;; reset the prefix arg, otherwise it will affect the ag-command
            (current-prefix-arg nil))
        (funcall ag-command search-term dir))
    (error "Ag is not available")))

Answer 3

You can use helm-ff-do-grep invoked in helm-find-files to grep any directory you want. It has a demo in there; the grep in Helm is incremental: it returns results for every character you type, effectively provides live feedback. Or use helm-projectile that is capable of invoking grep in any directory of selected file or directory in a helm-projectile-find-file or helm-projectile-find-dir. See the helm-projectile guide here.