Category: Tech

Debian server DNS bogosity

Note: I’m running my Raspberry Pi as a server, and NetworkManager is not installed. I discovered that if you want to manually assign search and nameserver entries in your /etc/resolv.conf file, you can’t just add the relevant entries to static entry in /etc/network/interfaces: [crayon-5eab0f9f8ea5b414288377/] For some unknown reason, the resolvconf utility will still attempt to

finger has a posse

Just saw this on One Thing Well, and it made me so nostalgic about my early years on *nix and the net. A weather service fed over the finger protocol. [crayon-5eab0f9f8ec14081953451/]

GNU xargs is missing the -J option. WHY!?!

I find that using an idiom like [crayon-5eab0f9f8ecd0611319066/] is so useful. It replaces the replstr (“%” in this example) with all the arguments at once, or as many as can fit without going over the system’s limit. I couldn’t believe it when I learned that the GNU version of xargs lacks this flag. Yes, it’s

Unison dependency hell

I would really like to rid myself of Dropbox, but all the alternatives I’ve tried are too bloated, beta- or alpha-quality stage, too complicated to set up, or just plain don’t do what Dropbox does (minus the sharing stuff, which I don’t care about). I don’t want btsync, it’s closed-source. Seafile is too complicated, and

WordPress performance problem with many posts

If you have a ton of posts in your WordPress blog (we have over 35K in one site at work), it turns out that the Previous and Next links on each post may be running a tough query on your database. I wanted to know why MySQL was using so much CPU and wrongly assumed

Allow webapps to make outgoing requests

I was experiencing a pretty bad slowdown while trying to use the admin pages of a WordPress site recently. The load on the machine was quite low, so I began to suspect that it was trying to call out to external services (facebook, pinterest, etc) that might have been blocked by CSF (configserver firewall). I

Prepare a PDF file for OCR

If you have some need to OCR some text from a PDF or image file, you may want to use a tool like tesseract to do the job. But it won’t take any old input file, you’ll probably need to convert it first. The first error I got from tesseract was [crayon-5eab0f9f8ee73130340196/] The Googles indicated

Discard first column without AWK

UPDATE: Major derp moment on my part, thinking that you needed a loop in AWK to print all but one fields. Commandlinefu just cause a forehead-slapping moment when I saw this in my feed: [crayon-5eab0f9f8eef4788797353/] So, it seems AWK wins again. Carry on. If you’re trying to print one or more particular columns from some

Raspberry Pi can do fast video encoding

Yes, the Raspberry Pi can do fast video encoding. Of course you normally wouldn’t want to re-encode any video with an ARM processor, but that’s not what we’re going to do here. We’re going to leverage the GPU. I should point out before proceeding that the input formats for re-encoding are limited in this method,

Clone hard disk with rsync

I recently wanted to move a system over to a faster, larger SSD. I didn’t want to have to re-install an OS, figure out which old files to transfer over, and then re-configure everything. That’s not a fun time in my book. Here’s what I did (on a live system, yeah!) to clone my disk.

Self-hosted open source RSS readers

I think I’ve tried pretty much all of them. After the Google Reader-pocalypse, one of the primary requirements was that I could host it myself. Bonus points go to apps that have configurable keyboard navigation (“j” to open the next item must be distinct from “space” to just scroll down in the browser), as well

Finding call-time pass by references in PHP.

While trying to move an older code base to a newer system and thus a newer version of PHP (5.3 -> 5.5), I knew that some of the code would need to be changed to avoid using some removed features. Specifically, I mean call-time pass by references. For those who don’t know, this is kind