Copy part of the file in the buffer

Question

I need to copy part of the file (with re-search-forward) to another file under the marker. I know how to use re-search-forward, but I have problems with buffer.

Am i right with my logic?

• 1) open needed file with temp buffer
• 2) create new buffer
• 3) find needed lines with re-search-forward and copy them in this new buffer
• 4) insert lines into opened file with insert-buffer-substring

Right now i have a function like this:

(defun my-insert-file-name (filename)
  (interactive "*fInsert file name: ")
  (save-excursion
    (goto-char (point-min))
    (when (re-search-forward "#here")
      (forward-line 1)
      (------something should be here-----)))

Answer 1

If I've understood the question properly, here's a starting point:

(defun my-insert-file-name (filename)
  (interactive "*fInsert file name: ")
  (let ((buf (current-buffer)))
    (save-excursion
      (with-temp-buffer
        (insert-file-contents filename)
        (goto-char 1)
        (re-search-forward "regexp")
        (append-to-buffer buf (point) (point-max))))))

What this is doing:

• Set buf to the current buffer.
• Insert the contents of filename in to a new temporary buffer.
• Go to the top of the temporary buffer and search forward for "regexp".
• Insert the contents of the temporary buffer from the line after the match to the end of the file back in to buf.