Irreal

Mike Zamansky’s been busy dealing with admissions for next year’s Freshmen and other professorial duties but he has found time to give us a new video in his Using Emacs Series. This one is about using dired-subtree and dired-narrow, two packages that can simplify working with Dired.

The first package, dired-subtree, allows you to open a subdirectory displayed in a Dired listing inline with a single key. Zamansky has mapped this to Tab, which makes a lot of sense. Another Tab and the subdirectory listing is collapsed again. That can be very handy when you want to peek in a subdirectory but don’t want to open a separate Dired buffer.

The second package—the one that Zamansky finds a game changer—is dired-narrow. The idea is that you can (temporarily) narrow the Dired buffer to just the files you’re interested in. That makes it easier to see what you’re working with—especially with long Dired listings—or to perform a mass operation on just those files.

Both of these packages are part of Fuco1’s dired-hacks collection. I’ve written about dired-hacks before, here and here. If you’re a Dired user—and you should be—take a look at the collection to see if there’s anything that could improve your workflow.

Abo-abo has added a new function to the swiper suite that fixes a couple of problems with swiper. The new function, swiper-isearch, acts more like isearch. The first thing you’ll notice is that multiple matches on a single line are treated as individual candidates as with isearch. You no longer have to use Ctrl+’ to choose the desired entry (although Ctrl+’ still works).

The second change is that an external process is longer called to process large buffers. Follow the “swiper-isearch” link above to see all the details.

Abo-abo likes the new function enough that he is using it for his default search mechanism. I’m being a bit more conservative—since I just updated swiper today—and have bound swiper-isearch to Ctrl+Hyper+s. So far, though, I like it a lot although I’ve only really used it in tests, not in my actual workflow. If, after a little more experience, I still like it, I’ll swap the bindings for swiper and swiper-isearch.

If you’re not already using swiper, you’re missing out. I recommend it without hesitation—it will improve your searching immensely. If you are a swiper user, check out swiper-isearch. The new swiper library is already in Melpa so you need only update your packages to get it.

Here’s a great tip from learn emacs on how to change a group of file names:

Need to change alot of file names in a directory at once? Dired to the rescue!

M-x dired

C-x C-q (to toggle dired buffer/dir read-only)

query-replace (or any other method to alter file names)

C-c C-c (save changes)

Done!https://t.co/kLBlnpGdGq #Emacs

— learn emacs (@learnemacs) April 5, 2019

I’ve been doing this for so long that I almost didn’t bother writing about it because I thought of it as something everyone knows. But perhaps not and that’s too bad because it’s a very useful technique. I use it even to change the name of a single file because the workflow is easy to remember and execute. Here’s an Emacs Rocks! video where Magnar Sveen uses the idea in combination with multiple cursors.

It’s definitely a habit worth cultivating if you’re not already using it. It will save you time and effort when you need to rename a set of files.

I’ve always felt a little bad that I have a hard time understanding how to work with Emacs fonts. Even simple things like setting the default font seems harder than it should be. It turns out that it’s not (just) because I’m slow: the font system really is hard to understand.

At least that’s what Alan Third says. He’s got a really useful article on how to work with the font system so you can do common things like configuring a backup font. That’s important if your default font doesn’t include the Unicode symbols that you use. For example, my default font, Inconsolata, is missing many of the Unicode symbols that I use so I had to download and configure the Symbola font to supply the missing glyphs. Third says that Emacs has an automatic fallback to Symbola so it may not be necessary to configure it. See what I mean about not understanding the font system? If, like Third, you need support for several Asian languages, you’ll appreciate his section on how to set things up to support the various fonts.

It turns out that Emacs will try really hard to find a glyph that matches the symbol you’re trying to use so in theory you really just need to make sure they’re on your machine. But that means Emacs has to search all the fonts you have installed so you’re better off configuring your fallback fonts so Emacs can limit its search space. On the other hand, if you’re using your configuration on a machine that doesn’t have that particular font installed, Emacs will just put an empty space in its place. Fortunately, Third shows you to get around that problem too.

The information in his post isn’t the type of thing you need everyday—or even often—but when you need to do something with fonts, it’s invaluable. It’s definitely worth bookmarking the post for when that day comes.

Update [2019-04-04 Thu 12:33]: your → you’re

Last month someone pointed to this Emacs Notes post from last year and I thought some of you might find it handy. As the post points out, syntax highlighting can be a wonderful thing but sometimes you have a weird or custom file format for which no highlighting has been implemented. The author gives a simple example of this and goes on to show how to implement your own custom highlighting.

It probably seems as if it’s not worth the trouble most of the time but once I got used to having syntax highlighting, files seemed “dead” without it. If you have files in strange formats that you use more than very occasionally, you should read over the post to see if it’s worthwhile providing some highlighting.