Last weekend I did the most stupid thing you can do when a new version of Ubuntu is released: upgrade. At least until things have calmed down a bit. Anyway, I didn't have much to lose, as things have been on a steady decline since the last LTS release.

My …

I've been playing with scikit-learn recently, a machine learning package for Python. While there's great documentation on many topics, feature extraction isn't one of them. My use case was to turn article tags (like I use them on my blog) into feature vectors.

[Update: Ported the code to scikit-learn 0 …

It's been a while since my last article on Matplotlib. Today we're going to plot time series data for visualizing web page impressions, stock prices and the like over time.

If you haven't already, install Matplotlib (package python-matplotlib on Debian-based systems) and fire up a Python interpreter. For the rest …

In Ubuntu's Unity, you get four workspaces per screen, arranged in two rows with two columns each. Fortunately, there's a way to get more desktop space, but in Ubuntu 11.10 it takes a bit of searching.

After clicking around for 20 minutes, I finally found a menu in compiz' …

When I started this blog in December 2006, I didn't think I'd keep going for five years. Now, more than a hundred articles later, there's still no shortage of topics to write about. Five years is like eternity in my line of business, so let's not dwell in the past …

When the Hudson/Jenkins fork was announced earlier this year, the case seemed pretty clear. There were heroes from the Open Source community, among them Hudson's original author, and there was everybody's favorite villain, Oracle. Back in February, I would have chosen Jenkins without a second thought. Now, almost a …

It's amazing how sometimes problems solve themselves. Since my last article, I got a new home router (a FRITZ!Box Fon WLAN 7320) that nicely solves the problem of accessing network devices with dynamic addresses even without Zeroconf.

My router also acts as a DNS proxy and provides a few …

Occasionally I want to transfer a file from my Linux desktop machine to one of my Android-based devices via my home network. Shouldn't be a problem, there are lots of networking protocols for this, right? In practice, many solutions you think of aren't convenient enough for daily use.

Services like …

From time to time, the virtual server I rented acted up. When logging into the system, I would get error messages indicating the server wasn't able to create any more processes: "cannot fork". This was weird because ps(1) showed only 20 processes, while the hard limit of the virtual …

JUnit 4 introduced a fancy DSL based on the Hamcrest framework for expressing assertions. JUnit ships with the most important matchers and you can always add Hamcrest to your classpath if you need more. Sometimes no existing matcher fits your needs and you have to roll your own. Since it's …