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Simplified: Idiot Tax

“If you can’t explain it to a six-year-old, you don’t understand it yourself”
— Albert Einstein

The opening quote is attributed to Albert Einstein, even though it’s unlikely that he used these exact words. Nevertheless, the idea behind it has always resonated with me: If you explain something in easy words the person at the receiving end can immediately grasp it and is enlightened forever. But reducing a topic to its essence and explaining it from the vantage point of somebody else is even well worth the time for the one at the giving end: As always, the teacher learns the most.

I recently held an embedded programming workshop for kids and what I took home is this: if you pick the right examples and metaphors, even 12-year-olds can understand topics like pulse-width modulation. With this post, however, I want to address adults; specifically, I want to talk about something that has puzzled me for quite some time: why do people, even highly educated people, take part in lotteries?

A common knee-jerk reply is that everyone wants to get rich quick, without earning it. But that’s not the answer I am looking for. Let me refine my question: why do people play lotteries even though they know that the odds of winning are infinitesimally small?

Let’s take the German lottery system as an example. In order to become a millionaire, you have to get six numbers right, out of a total of 49. According to their official website, the odds to get these six numbers right are 1 to 15.537.573, or roughly 1 to 15 million.

Even though our gut feeling tells us that this is quite unlikely, we completely underestimate how unlikely it really is. Why? My guess is that it’s because we hear about figures that are in the millions every day. This guy is a millionaire, and that one even a billionaire. Government spends millions here and billions there. Still, we are nothing more than remotely acquainted with large numbers; we constantly fail to truly and fully comprehend them.

Let’s use an approach that has helped me quite a lot and treat big numbers like distances. What the human species has done for thousands of years is walk, so we naturally have a good grasp on distances. Let’s pretend we have a distance of 15 million centimeters.

15 million centimeters divided by 100 gives us 150 thousand meters, which equals 150 kilometers. People are especially good at understanding kilometers. 150 kilometers means roughly a two-hour car ride on a regular country road. That’s quite a distance, isn’t it?

Further, imagine a single M&M chocolate piece. It’s diameter is roughly one centimeter, give or take. Put one M&M after another, on a single straight line that is 150 kilometers long and you get what the number 15 million looks like. Somewhere along that line, there is that one special M&M where they printed a “$” sign on the back, instead of the usual “m”. So you drive along this 150 kilometer line with your car, stop at some random point and flip a single M&M of your choice, hoping to see a “$” sign on it’s back.

Now, how much money would you invest in such a bet? I don’t know about you, but I wouldn’t even invest a single cent. While it’s not impossible to win, it’s very, very improbable. Any money would surely be gone.

This is why the enlightened call lotteries “idiot tax”. It’s the tax that people—out of greed and ignorance—pay voluntarily.

Oops, They Did It Again!

“There are no secrets that time does not reveal.”
— Jean Racine

In an act of unprecedented arrogance, Apple once again dictated to their users what they believe is good for them — this is yet another example of how they take away their users’ freedom.

Yesterday, they finally admitted what measurements by various users had suggested earlier: one year ago Apple introduced a feature that deliberately slows down the performance of older iPhone models in order to “deliver the best experience to their customers”.

This is, of course, total BS. It’s obvious that the real motive was to boost sales of their new products. Why? Because they kept it secret. Period.

If they really had the best of their customers in mind, they would have announced such a drastic step in good time. Further, they would have given their users a choice (something totally alien to them) by presenting a simple opt-in dialog:

Dear loyal customer, we’ve discovered that the capacity of your phone’s battery has become low. We strongly suggest that you either a) buy one of our latest models, b) replace your battery (which will cost you many $$$, because you can’t do it yourself), or reduce the CPU performance which will DELIVER THE BEST EXPERIENCE to you. What do you want us to deliver to you?

1. Our latest iPhone model
2. A replacement battery
3. The best experience

Some time ago, I wrote a post which details why I don’t buy iThings and this recent incident just adds to the list. However, I’m enough of a realist to doubt that it will reduce the total number of iThings under this year’s Christmas trees.

The Right to Choose

Shame on me! For the first time in a decade, I forgot to celebrate Towel Day. The fact that my towel proved so incredibly useful a couple of days earlier makes me feel even guiltier.

Douglas Adams is admired by most of his fans because he was not just tremendously funny, but also a shrewd freethinker who loved to show people how limited and simple-minded their views and beliefs are (anyone remember the Total Perspective Vortex?). But actually, he himself had his eyes opened one day by another person: in an interview with BBC, Douglas Adams disclosed that one of the most influential, eye-opening books he had read was “The Blind Watchmaker” by Richard Dawkins.

In his book, Richard Dawkins demonstrates that by Darwin’s Theory of Evolution and natural selection enormous complexity can arise out of even the simplest building blocks and that there really is no need for a Creator. Douglas Adams and Richard Dawkins were so like-minded that it’s no wonder they later became close friends.

At the end of one of his talks, Richard Dawkins presents a slide titled “The Illogic of Default”, which demonstrates the ill-reasoning of many Creationists:

1. We have theory A and theory B
2. Theory A is supported by loads of evidence
3. Theory B is supported by no evidence at all
4. I can’t understand how theory A explains X
5. Therefore theory B must be right

This exactly describes what happend to me one day when a muslim taxi driver tried to “prove” to me that there indeed must be a god. “See”, he said, “the theory of evolution just can’t be right. If we humans are really decedents of animals like apes and dogs, why are there still apes and dogs around?”.

I refrained from arguing with my taxi driver, even though it was obvious that he didn’t understand the Theory of Evolution at all. How could I resist the temptation?

I absolutely admire Richard Dawkins for his wit and I recommend that you watch all of his Youtube talks and videos, but there is a problem with atheists like him: sometimes, they are just as annoying as followers of any other conviction when they try to foist their views on others. Even if we know that Creationist’s arguments are utterly wrong from a logical and scientific point of view, it doesn’t help: it’s a documented fact that a significant part of humankind has a strong desire for spirituality. And, as we all know, whenever strong desires are involved, appealing to logic doesn’t work: drug addicts do know that drugs ultimately kill them but they nevertheless don’t quit.

Likewise, deep in their hearts, many believers in god assume that there is no god, at least not one like the one that is depicted in the holy scriptures, but they need a god for their mental well-being, anyway. Trying to prove to them that there is no Creator is a) futile and b) hurts them — not physically but emotionally. This is why I didn’t argue with the taxi driver. I strive to follow the Golden Rule, which — incidentally — also appears in many holy scriptures: always treat others the way you want to be treated.

So why I and many other people prefer to have their eyes opened, others don’t. Everybody should be free to choose the color of the pill they take.

Working the Bash Shell Like a Pro

“People drive cars with steering wheels and gas pedals. Does that mean you don’t need wrenches?”
— Rob Pike

I’ve always preferred command-line interfaces (CLI) over GUIs. If I use GUIs at all then it’s mostly for browsing the web. Luckily, there is a plugin for my web browser that allows me to do most of my surfing using vi keystrokes. Yes, I try to avoid the mouse as much as I can.

I believe that most people who prefer GUIs either are bad at typing or haven’t taken the time to learn to use a CLI in an idiomatic way. With this post, I want to share some Bash CLI idioms that can significantly improve your efficiency. I don’t aim for a complete list — I rather present a compilation of the most frequently “not-known” techniques that I’ve encountered when I observed people working with Bash.


First of all, make sure that you have enabled the command-line editing mode that suits you best. You are much more productive when your favorite shortcuts are available:

Often, we need to do something that we’ve already done before. You can easily re-execute the previous command with this shortcut:

Courtesy of this operator, forgetting to put ‘sudo’ in front of a command is not a big deal:

If you want to re-execute “one of the previous commands” instead of the last one, you could use the following abbreviations:

However, I don’t find these history expansions particularly useful. Often, going through the history by pressing ‘Arrow Up’ is equally fast.

The real game changer, however, is CTRL-R. Press CTRL-R and start typing any characters from one of your previous commands. This will start a backwards search through your command-line history and present you with the most recent command containing the characters you typed (or continue to type). Pressing CTRL-R again will find the next most recent command and so on. If you only partly need what you typed in the past, no problem — you can always edit the command-line that CTRL-R found before executing it.


If you want to rename a file, please don’t do it like this:

Even with TAB completion, this requires too much typing. Why not reuse the path of the first argument?

‘!#’ is a shortcut for “the command-line typed so far” ‘:1’ selects the first argument and ‘:h’ strips off the last component (ie. “oldfile”).

In some cases, you don’t want to rename the file entirely but only change the extension. This can be achieved in a similar fashion:

You guessed it: ‘:r’ removes the file extension.

What if you did a mistake and wanted to undo this change? Again, that’s quite easy if you know the trick:

Which translates to “do another move but swap the arguments from the previous command”.

Sometimes, my fingers get ahead of me and I type ‘vm’ instead of ‘mv’:

Of course, you can always edit the last command be pressing ‘Arrow Up’ and change ‘vm’ to ‘mv’, but the following is much easier to type:

‘!*’ is a placeholder for “all arguments of the previous command”.

The word designator that I use the most — by far — is ‘!$’; it expands to the last argument of the last command:

Many times, people gratuitously reach for the mouse to copy the output of a previous command in order to use it as an argument for another command. Why not use ‘$()’ to capture command output?


If I was asked to name my favorite standard command-line tool, no doubt I would pick ‘xargs‘. Even though it is largely useless by itself, it’s the superglue that allowes you to build powerful command-lines. It takes the output of a command and uses it as arguments for another one.

Here’s an example that uses ‘xargs’ to build a tar archive containing all the C files that contain C++ comments:

In rare cases, when I have to do work that involves complicated selection/filtering, I reach out for TUI (usually ncurses-based) applications like ‘tig‘, ‘vifm‘, or ‘mc‘ that run in the shell and can be fully operated by the keyboard. Nevertheless, I first try to get by with the simpler ‘menucmd‘ tool. Here’s an example that builds a menu from all shell script files found in a directory. If the user selects an item, the specified action (‘cp -t /tmp’) is executed on it.

There you go. Even if this bag of tricks is not complete I hope it will serve you well. As always, in order to use a tool efficiently, you have to invest in learning how to use it idiomatically*. But this investment pays nice dividends in the medium-to-long term.

*) What’s the idiomatic way for vi users to underline a headline? 1. Yank the headline (‘yy’). 2. Paste the yanked headline under the exiting headline (‘p’). 3. Select the second headline (‘V’). 4. Replace every character in selected line with an underscore (‘r-‘) — that’s only six keystrokes! Awesome!

Why I don’t Use Apple Products

Every now and then, people ask me why I steer clear of iThings. Explaining my view over and over again is tedious, so I’ve decided to present my reasons in writing. When this topic comes up next time I just need to point people to this post, which will save a lot of time on both sides.

Open-source veteran Richard Stallman, founder of GNU and the Free Software Foundation (FSF) has already contributed his share to the topic. I do agree with most of his arguments but I still want to tell the story from my point of view.

First of all, let me emphasize that it has not always been like that. As a matter of fact, I used to be an Apple fan myself, even though this was in the early 1980s. My first home computer was an Apple II clone and I badly wanted to own a real Apple II, I can tell you. Alas, it was too expensive for an eighth grader’s measly monthly allowance.
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Two German Maxims That Will Save Your Neck (and Others’ Necks as Well)

I quite remember the uneasy sensation that I had when a former coworker told me a story — a story about a senior engineer who went to jail because of a bug, a fatal one, as it turned out.

The bug lurked in an electronic control unit (ECU) which was, among other things, controlling the manual deactivation of the front passenger seat’s airbag. Under normal circumstances, you wouldn’t want to disable an airbag, a feature that saves lives every day around the world. However, if you intend to put a rearward-facing baby seat in the front, you have to do it, or you risk severe injury of your child in case the airbag deploys during an accident.

Now, this unfortunate engineer discovered that under extremely rare conditions there was a tiny window of opportunity for the airbag deactivation mechanism to fail silently; that is, it would appear to be deactivated when in fact it wasn’t. I don’t remember the necessary prerequisites, but what I do remember is that the combination of inputs and actions sounded so silly, so unusual, so improbable that he — like probably most of us would have — expected that the fault would never ever show up in practice. But what a terrible mistake this was, as this is exactly what happened and a child lost its life.

How unlikely or likely is the higly improbable? The chances of winning a 6-number lottery game are typically 1 against many tens of millions; yet, the likelihood that some player (not a particular player, of course) wins is quite high. Why? Because there are millions of players who take part in such lotteries. The same is true for ECUs which frequently find their way into millions of cars.

The developer was punished not for creating the bug but for not telling his managers about his discovery, for keeping it secret. But why didn’t he report the problem to his superiors? I can only guess. Maybe there was a lot of schedule pressure, perhaps he didn’t want to upset his boss. Or, the product was already released and a recall would have cost a lot of money, let alone reputation. If you ask me, it was a deadly cocktail of fear and pride.

When I did my military training at the German Armed Forces, one of the first rules I learned was “Melden macht frei”, which more or less translates to “reporting is liberating”. It is your duty to report an incident and it has a liberating effect on you, both emotionally and legally. After reporting, it is your superior’s problem. He has to decide what to do next. That’s not dodging responsibility — it’s passing on an issue that is outside your area of responsibility to the right person.

In the same spirit, as professionals we also have to report any issue that is harmful to customers or the company, regardless of how unlikely it appears to us. Even if management makes a (hopefully prudent) decision to ignore the problem (like it was the case in the Space Shuttle Challenger disaster, where engineers clearly raised their concerns that the O-rings on the rocket boosters would not seal at low temperatures), at least you have behaved professionally and are saved from prosecution and guilt feeling.

There is, however, a strange phenomenon: People sometimes forget that you informed them, especially when they have to testify in court. That’s why I want to share another important German wisdom with you: “Wer schreibt, der bleibt”, which can be translated as “you write, you stay”. It means that (only) if you write something down, you will be remembered. In other words: always keep a paper trail; email usually suffices.