Irreal

Regular readers know that one of my New Year’s resolutions is to learn more LaTeX. I’ve been having a lot of fun learning and using AUCTeX to write LaTeX documents. I created a tex directory to hold my .tex files and the resulting PDFs. The problem with TeX is that it’s pretty noisy as far as creating intermediate files is concerned and those files mostly stick around. But, hey, this is Emacs so I thought, “I’ll just write some quick Elisp to clean things up.”

I hadn’t gotten around to that when I decided to scroll through some of abo-abo’s old posts to see if I’d missed anything. Good thing I did because it turns out that there’s already a way clean up garbage from directories. Here’s what to do:

1. Bring up the target directory in dired¹. 【Ctrl+x Ctrl+j】 is often a good way of doing this.
2. Press 【%】【&】 to mark the “garbage” files.
3. Press 【x】 to delete the files.

That’s all there is to it. Exactly what constitutes garbage is determined by the dired-garbage-files-regexp variable. It defaults to

"\\(?:\\.\\(?:aux\\|bak\\|dvi\\|log\\|orig\\|rej\\|toc\\)\\)\\'"

but you can customize it to include other types of temporary files you deal with. You can check out abo-abo’s post for one example of this. If you’re a neat-freak about your file system, this is good way to keep things spic and span.

UPDATE: See the comment by David McWilliams on how to do this from AUCTeX (for TeX detritus, of course). Very Handy.

Bozhidar Batsov over at the excellent Emacs Redux has a very nice post on how to clear comint buffers. Comint is the machinery behind Eshell, and Shell mode. It is a general-purpose mode for communicating with interactive subprocesses and is thus behind many of the REPL systems such as Lisp and Ruby.

Oddly, comint has no way of clearing the buffer, something I’ve often wanted when working with Eshell. Bozhidar shows us how to do that with just a few lines of Elisp. If you use any of the comint-based mechanisms, you should take a look. It will make your life just a bit easier.

Grant Rettke points to a discussion in the comments from a Sacha Chua post. It turns out that when you’re in multiple cursors you can narrow the view to just those lines having a cursor. That’s something I didn’t know.

All you need do is turn on hide-unmatched-lines-mode. You can do that by typing 【Ctrl+'】. This is nice because it eliminates a lot of clutter and allows you to concentrate on the text you’re changing. Where is really shines, though, is with a large buffer where you normally wouldn’t be able to see all the cursors.

Actually, hide-unmatched-lines-mode will provide some context—2 lines above and below each cursor, by default—but, of course, you can configure that. This is another great enhancement to one of my favorite packages. Another gift from Magnar Sveen.

If you took my advice and starting following (or emacs you’ll be familiar with abo-abo’s hydra package. It started out as a relatively simple macro, def-rep-command, that allows a command with a prefix to be repeated by merely pressing the last key. That got a lot of favorable attention so he refactored it into an ELPA package.

Then Sacha picked it up and made a small enhancement that allowed her to use it to control window switching. Since then, abo-abo has made continuous enhancements to the package making it a very flexible tool. Now abo-abo has produced a video that demonstrates its power. The video shows hydra being used for a variety of different tasks and will be sure to give you some ideas.

If you follow the link above, it will take you to a post by abo-abo that, in turn, has a link to the video. It also shows the current version of his window switching code. You’ll see that it now handles most of usual window handling chores including calling ido for another buffer and loading frequently used files with a single key by bookmark+. You can also call executable code so it has about the same power as John Kitchin’s Emacs/Helm hotspots setup that I wrote about previously.

I have to say that I’m really tempted by this. It seems like a nice way of loading frequently used files and switching between, swapping, and deleting windows. It has the advantage over Kitchin’s solution of loading hydra, which can be useful for other chores. On the other hand, the same can be said of Helm. A fine example of Buridan’s ass.