Problem: I'm trying to write a command that takes the selected text and appends it the end of a file of my choice.

There also needs to be a tab completion (or autocompletion) element to the command, in the sense that the command should be able to autocomplete to files that are nested somewhere within the directory /tab/completion/directory.

Example: Suppose there is a file /tab/completion/directory/nested/file.md, and I select text in my buffer and run M-x append-to-file, then I should be able to M-x append-to-file file.md<TAB> for it to autocomplete to M-x /tab/completion/directory/nested/file.md. After running this command, the selected text should be sent to end of the file.


I don't know if I understand your question, append-to-file already appends the selected region to a file you specify:

append-to-file is an interactive compiled Lisp function in ‘files.el’.

(append-to-file START END FILENAME)

Append the contents of the region to the end of file FILENAME.

As for completion, I recommend you strongly consider the ivy/swiper package.



If you are trying to find the file without knowing the path then you probably want to look at projectile-find-file. Then write a function that calls append-to-file and projectile to fill in the filename.

  • I already have projectile and helm. I'm totally new to elisp. Can you demonstrate (or at least sketch) how to call append-to-file and projectile to fill in the filename? – George Jul 10 '17 at 13:18

If you are using ido see introduction here, then all code you have to write is this:

(defun my-append-to-file (file)
    (interactive "Ffilename")
    (write-region (mark) (point) file 'append))

You could also use M-x write-region directly.

  • This works to append text to the end of a file, but it doesn't seem to have autocomplete features for nested filenames. – George Jul 10 '17 at 13:20
  • The autocompletion is done by ido. If you use ido you have autocompletion on every operation in minibuffer, which uses filenames or buffernames. This is really nice. Please have a look at the Introduction link I provided in my answer. – jue Jul 10 '17 at 14:16

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