Emacs: Helm for finding files

From Amit’s Thoughts

When using Emacs I’m often switching buffers or opening files, so I’m always on the lookout for ways to make those operations more pleasant.

A while ago I tried Anything.el. Anything is like Quicksilver for Emacs. It’s powerful but I found it confusing to set up. Emacs-Fu had a blog post about configuring anything.el, and I used that for my setup.

For the most part, I use it instead of find-file:

When I saw that Helm was the successor to Anything, I decided to switch to Helm and simplify my setup. I was pleasantly surprised by how easy Helm was to set up compared to Anything. Here’s my setup, binding Alt+T (inspired by Textmate) to invoke helm-for-files:

(require 'helm-files)
(setq helm-idle-delay 0.1)
(setq helm-input-idle-delay 0.1)
(setq helm-locate-command "locate-with-mdfind %.0s %s")
(loop for ext in '("\\.swf$" "\\.elc$" "\\.pyc$")
      do (add-to-list 'helm-boring-file-regexp-list ext))
(define-key global-map [(alt t)] 'helm-for-files))

This uses the default helm-for-files setup, which lists, in order:

1. ffap (find file at point)
2. buffers (names of all open buffers)
3. recentf (recently opened files)
4. bookmarks (which I don’t use)
5. files-in-current-dir (like find-file)
6. locate (files in other directories)

However, I don’t want locate for all files on my disk; I want my home directory, minus a few subdirectories that contain files I never open. For this, I use a shell script to filter the results. On a Mac, use mdfind -name instead of locate; it’s updated in real time instead of nightly. I use a more complicated script that also handles patterns like foo/bar.txt:

#!/bin/bash
# Note: updated 2014-03-28 to handle patterns like foo/bar.txt
suffix=$(basename "$@")
pattern="${suffix}*"

if [ "$@" = "$suffix" ]; then
    # If there's no folder then it should be a substring
    pattern="*${suffix}*"
fi

mdfind -onlyin $HOME "kMDItemFSName = '$pattern'cd" \
    | fgrep -i "$@" \
    | grep -v "$HOME/Library/" \
    | grep -v "$HOME/Pictures/" \
    | grep -v "$HOME/Music/" \
    | sed -e "s|^$HOME|~|"

(Note: if you want to use mdfind to search contents and not only filenames, take a look at helm-source-mac-spotlight.)

More thoughts:

• Ideally, I don’t want to have to think about whether I’ve already opened a file or not. In practice I do treat switching buffers and opening files differently. I use Alt+J and Alt+K for switching buffers in the same directory (see this blog post). I sometimes use ido-find-file (bound to Alt+O) for opening a file in the same directory, but I’m increasingly using helm-for-files even in the same directory.
• Since mdfind is so fast with an SSD, I reduced the initial delay from 300ms to 100ms. That made it feel much better. You may need to experiment with the delay setting.
• The same file can be in the buffers list, the recent files list, the current directory list, and the locate list. I’d like to see each file only once. I’m sure helm can filter these out but I don’t know how.
• It'd be nice to not have it print out the full path every time, but I haven't figured out how to do that.

There are so many amazing things Helm can do; I’m only using it for this one feature, and it’s been great.

Update: [2014-03-28] I updated the "locate" script I use to allow finding patterns like foo/bar.txt. Normally, mdfind won't find these because it only sees bar.txt.

Update: [2014-05-27] Also see LocateFilesAnywhere on EmacsWiki if you're looking for Emacs packages that let you find files from anywhere, not only the current directory. I'm no longer using the above setup.

Labels: emacs