Matthias Nehlsen

Software, Data and Stuff

Weekly Update: git vs brain fart, Octopress, Sony A7, my audio setup

In this weekly update, I will show you how git helped me alleviate the disastrous consequences of a brain fart. I will also share my experiences with Octopress. You will learn what helps me feel better, day in and day out. Then, I’ll talk about some changes regarding the mailing list for this blog. And last, there’ll be reviews on my audio setup for a combined work / chill area and on the Sony A7 full frame camera.

git vs brain fart

The other day I experienced a curious malfunction of my brain. I had some uncommitted changes in a repository. Many hours of work in fact, way more than I normally would leave uncommitted anywhere. So to alleviate this grievance, I typed git add . on the command line.

So far so good. But then I got distracted by a rather annoying phone call. During that call, something happened that I can best describe as a brain fart. I typed git reset --hard HEAD and pressed ENTER. Now you will probably ask why anyone would want to do that, particularly before actually committing the changes. To be honest, I am clueless. Maybe it was the geek’s version of a Freudian slip? Something in my brain probably wanted to reset itself to the happier pre-call state, but somehow that idea landed on the command line instead?

In case you don’t know this (destructive) git command, this is what it does:

Resets the index and working tree. Any changes to tracked files in the working tree made since will be discarded.

Okay, think about that for a second. The documentation says it loud and clear. Changes to tracked files since HEAD, which is the current commit to which I have added above but not committed, are discarded. Oops.

I have no idea what I was thinking. My changes appeared to be lost forever. Not a surprise really when you think about the description above. But for me in that second it was like getting hit by a truck that came out of nowhere.

So I really wanted the fruits of my previous and tedious labor back.

I tried git reflog according to these instructions, but that did not help; I did not find anything useful in the output. Luckily though, fsck helped:

git fsck --lost-found --verbose
cd .git/lost-found/other/
find . -print | xargs grep someUniqueTextHere

So basically, git only runs a garbage collection every once in a while. I found this here. Using the commands above, I tell git to run a fschk and write out the lost and found items. Then I can find the one I was looking for by piping the result of find in that directory to grep, looking for some specific text I remembered from the work I had lost.

Then from the files I found, I was easily able to reconstruct the work that previously appeared lost. That really saved my day.

ClojureScript article

I found some time to put additional work into the article in which I describe the recently added ClojureScript client of my BirdWatch application. Initially I wanted to do more work on the application itself and specifically use Transit instead of JSON parsing. But this application is fairly dependent on keywordized keys inside the representation of the tweets, and Transit as of now does not have a built-in way to keywordize the JSON property names so that would have been a bit of work. Totally doable and the only thing that keeps me from actually doing it is that I want to do some major redesign of the application. Then, that effort would likely be wasted. More on that soon.

Octopress, one year later

I am using Octopress to generate my blog. It has served me alright, but I don’t really like it a lot and probably wouldn’t use it again. I am just not enough of a Ruby guy to tinker around with it. I cannot even fix issues when I try to update it. The other night I wasted two precious hours trying to get my installation current so that I would benefit from newer features. I didn’t succeed. Quite frankly, I have no intentions of becoming a Ruby expert any time soon or ever.

Along those lines, I was thinking about rolling my own blogging engine. Yeah I know what you’re thinking. At some point every (technical) blogger will reach that stage where you want to create your own blogging engine. But hear me out, this one might be a little different. I am thinking about making use of Polymer and Web Components. Now that the Google robots run JavaScript, the blog would get indexed just fine, without pre-rendering for search engine visibility. Why not load the markdown directly from a web component handling the current post and then let that render itself? Polymer handles browser compatibility, but I do not care much about IE6 users and the like anyway. At the same time that would give me a chance to delve deeper into web components. The idea of a shadow DOM is just brilliant, and I hope web components will have the success they deserve. Finally a vendor-agnotic way of building web applications.

Feeling good

I have a lot of fun writing stuff at the moment. I also write for myself. The first 25-30 minutes in the morning belong to me and me alone. Before reading any email, I focus on everything that comes to mind and write it down. It’s a great way to gain some clarity on what I want to do and where I want to go. The only thing that’s missing in the process is a decent and searchable way to organize the notes. That part needs work. But nonetheless, I am a happier person when I do this regularly. Highly recommended.

Mailing list: one and only one

At first I thought about creating a separate mailing list because I didn’t want to spam anyone who subscribed for infrequent tutorials with weekly updates like this one. But that’s too much work on my end. So instead I will unify the mailing lists. If the updates are too frequent for any of the existing subscribers, there are two options: a) let me know or b) unsubscribe. But why don’t you give it a try? My intention is to make the weekly update an entertaining read.

Book and gadget reviews

Last week I mentioned that I wanted an outlet for my opinions on books and gadgets. So I created a page for reviews. I also started writing about some electronic stuff that I own.

My audio setup

I recently kicked out a high-end surround sound system in favor of a mixer, two active speakers and a pair of headphones. Find out why.

My camera, Sony A7

I can finally use my classic Zeiss and Leica prime lenses again thanks to this camera. Overall I am quite happy with it. This review is a work in progress, but you can already read some of it here.

Have a great week, Matthias

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