Welcome

This is my home in the virtual world, where I write about things that I want to share. The freely available software that I've written as well as some of the photographs I've taken over the years can also be found here. Please use the navigation links on the right if you are looking for something.

Recent articles

1. Have Python log to syslog

   This article documents how I set up Python and the syslog daemon so that Python programs can log to syslogd.

2. Command-line versus GUI program

   TL;DR

   When you are exploring a problem, in general first write a command-line program whenever possible.

   It will take less effort to write then a full-blown GUI.

   Introduction

   Recently I wrote a program to remove the protection from ms-excel files.

   The original version was written as a command-line program. Later I re-used the relevant code for a GUI program for use on ms-windows. This was mainly for the benefit of some colleagues who are not comfortable with using the command-line.

   In this article I want to contrast the two programs.

3. Creating a screenshot in X11

   Creating a screenshot from a terminal, using standard UNIX tools.

4. How convenient is multithreading compared to multiprocessing?

   There are basically two ways in which one can make use of a modern CPU with multiple cores for computationally intensive work.

   1. Using multiple threads within one program (multithreading).
   2. Using multiple (single-threaded) programs that communicate (multiprocessing).

   In the first case, all data is implicitly shared. In the second case, data must be explicitly shared or communicated.

   The first option is often said to be more convenient. I would like to make the case that this usually makes the task more difficult, because of the need to manage all shared data.

5. Roll back a FreeBSD port with svnlite

   Sometimes I’m too hasty with updating ported applications, and I need to roll them back to a working version. Since I use svnlite to manage my ports tree, this is relatively easy. But since it is different than I’m used to (since I mostly use git), I thought I would document it here for convenience.

6. Including binary data in Python scripts

   Sometimes I need to use some binary data (e.g. a bitmap image) in a Python script. In a package, you can store this data portable in a data subdirectory of a modules using the package_data argument of setuptools.setup. This won’t work in a standalone script. You can of course make your script into a package, but here I want to show an alternative solution.

7. Testing compression speed and ratio

   The compression speed and ratio of several compression programs is tested.

8. My e-mail setup

   For years I’ve been using fetchmail and procmail for incoming mail. However, both of these programs haven’t been maintained for years. So it was time to change.

9. Luminous clouds

   My balcony gets the evening sun. Sometimes the sun and clouds make for a stunning view. See below.

10. A simple feed reader for Youtube

    As an exercise, I wrote a small script to read the Atom feeds for some favourite youtube channels. Of course I could have installed a “real” feed-reader, but that would be overkill and not half as much fun. :-)