Beat the Save Habit

It only takes one unfortunate program crash where you lose a lot of work to teach you the importance of saving often. I use emacs most of the time, and I had developed a nearly subconscious, paranoid habit of hitting c-x c-s every 5 seconds or so while working. I was starting to catch myself before hitting that save-buffer shortcut even when I was typing in other applications: instant messenging, web page forms, you name it. Meanwhile, I also started noticing applications that didn't require me to tell them to save my precious work. Gmail and blogger come to mind right a way. "Why couldn't emacs do the same?" I wondered. After hashing it out in that blog entry and on the emacs wiki, I added the following to my .emacs file, and I am happy to report that my twitch is gone:


(defun save-buffer-if-visiting-file (&optional args)
  "Save the current buffer only if it is visiting a file"
  (interactive)
  (if (buffer-file-name)
      (save-buffer args)))

;; This causes files that I'm editing to be saved automatically by the
;; emacs auto-save functionality.  I'm hoping to break myself of the
;; c-x c-s twitch.
(add-hook 'auto-save-hook 'save-buffer-if-visiting-file)

;; save every 20 characters typed (this is the minimum)
(setq auto-save-interval 20)

;; save after 1 second of idle time (default is 30)
(setq auto-save-timeout 1)

Now emacs automatically saves my work for me, without me having to ask, and I love it. It makes me a little nervous when I'm working on a file that's not under revision control, but with modern revision control being so easy to set up and use1, that is happening less and less.

If you see any way to improve this, or if you just want to tell me why it's dumb, please comment. My emacs lisp skil1z are pretty feeble.

1 Just type hg init, bzr init, or git init in the directory where the file lives and you are up and running.

Comments

Anonymous said…
I believe there is an easier way to do this:
,----[ (info "(emacs)Auto Save Files") ]
|
| If you want auto-saving to be done in the visited file rather than
| in a separate auto-save file, set the variable
| `auto-save-visited-file-name' to a non-`nil' value. In this mode,
| there is no real difference between auto-saving and explicit saving.
`----
March 19, 2008 at 8:10 PM
Bryan said…
Yes, I read the same thing and thought the same thing. You have to try it though. With that setup, once auto-save saves your work in the file the buffer is considered out of date and you can't continue editing without emacs continually asking you if you are sure you want to edit a buffer that isn't in sync with its file. Very very annoying.
March 19, 2008 at 8:58 PM
Phil said…
Extra credit: increase the auto-save interval when on battery power to allow the hard disk's spinning down to actually save power.
March 20, 2008 at 1:53 PM
Bryan said…
Ha! That's one I hadn't thought about. I'm on a desktop at work most of the time, and and besides, my laptop doesn't have a spinning hard drive ;-)

Does auto-save cause the disk to spin up every time it checks whether the file needs to be saved? I doubt that. If you are sitting there thinking and not typing, the auto-save interval shouldn't matter much.

Does auto-save cause the disk to spin up every time it saves? Probably not every time, there's all kinds of caching going on in RAM and in the hard drive device itself.

So, I'd be surprised if the auto-save interval will affect your battery time that much. Someone will have to try it to be sure though.


That being said, I wouldn't mind seeing what the emacs lisp that determines whether you are on battery power looks like ;-)
March 20, 2008 at 2:36 PM
Anonymous said…
That is exactly the right idea. "save" is something that should have never been introduced into personal computing. Your operating system should smoothly track everything you do.
March 21, 2008 at 7:13 AM
Anonymous said…
Here's a variation that does it only for files that are actually under version control. I'd be totally paranoid about automatically saving files like this on files where I don't have access to older versions.

;; Save files automatically if they're under version control
(defun save-buffer-if-visiting-vc-file (&optional args)
"Save the current buffer only if it is visiting a file and the
file is under version control"
(interactive)
(if (vc-backend (buffer-file-name))
(save-buffer args)))
April 2, 2008 at 9:36 AM
Post a Comment

Popular posts from this blog

SystemVerilog Fork Disable "Gotchas"

This is a long post with a lot of SystemVerilog code. The purpose of this entry is to hopefully save you from beating your head against the wall trying to figure out some of the subtleties of SystemVerilog processes (basically, threads). Subtleties like these are commonly referred to in the industry as "Gotchas" which makes them sound so playful and fun, but they really aren't either. I encourage you to run these examples with your simulator (if you have access to one) so that a) you can see the results first hand and better internalize what's going on, and b) you can tell me in the comments if this code works fine for you and I'll know I should go complain to my simulator vendor. OK, I'll start with a warm-up that everyone who writes any Verilog or SystemVerilog at all should be aware of, tasks are static by default. If you do this: module top; task do_stuff ( int wait_time); #wait_time $display ( "waited %0d, then did stuff" , wa
Read more

'git revert' Is Not Equivalent To 'svn revert'

I just learned that if you have some changes in your working tree that you want to get rid of, you don't type 'git revert' like you might guess. No, that's what cvs, subversion, mercurial, and bazaar (to name a few) use revert to mean, but not git. With git, revert is used to undo actual commits. Thankfully, you can undo your revert with another 'git revert', I just learned. So let me repeat to be clear, if you have changes to your working files that you want to abandon, DO NOT do this: git revert HEAD That will undo your last commit. Do this instead: git reset --hard HEAD I'm glad I have that straightened out now. I'm wondering if /etc was really a good place for me to start out playing with git. UPDATE: Nearly two years later and I'm still getting comments on this. I'm glad I've been able to help people out this way. The discussion in the comments is good, and one thing I'd like to point out is that I now always use
Read more

Put /etc Under Revision Control (with git)

UPDATE : There is a much easier way now : sudo aptitude install etckeeper There, now etc is under revision control and changes are automatically committed with a helpful message after you install new packages. Thanks for the tip, Marcelo! Read on for the original blog entry. --- I put my /etc directory under revision control. I used git. It's awesome. Not that I think I'm going to wholesale copy my /etc from one machine to another, nor because I'm going to branch my /etc directory and spend weeks developing some cool new feature (whatever that would look like...) and then merge it back into the main branch. No, it's mostly because I like the idea of having the big "undo" option that having things under revision control provides. Having to commit changes and write check-in comments when I make changes helps me stay more organized too. It's never good when I go in willy-nilly to make a "quick change" to some configuration file. I r
Read more