A key aspect of good photography is exposure - the amount of light that enters the lens.  One of the most useful tools a digital cameras has to help you measure a photograph’s exposure is the histogram. In order to learn how to use it, you must first learn understand what a histogram is.

Let’s pretend I teach a class of 20 students. One day I decide to give the students a test in which they can score anywhere from 0 to 100 points.  After grading the tests I want to see how the population of students did.  So I graph the scores in a histogram. A histogram displays the distribution of measured values across a population.  Let’s make one now.

[Another in my series of posts on Vim]

If you’re a developer, you will often find yourself having to insert a line of dashes or hashes (#) or asterisks into your comments.  In this post I’ll show you how to do this quickly.  Memorize this because you’ll wind up doing this often.  Position the cursor to the beginning of a blank like (in command mode) and enter the following:

80a#<ESC>

Let’s say you have two text files, FileA and FileB.  You want a file that has all the lines of FileA that are not in FileB.  How do you do that?

The simple answer is grep. The -v option inverts the search, and only prints lines that do not match.  The -f option is used to specify a file that contains a list of all the patterns for which to look - one pattern per line.

I don’t like running unless I’m running towards something or away from something.  But I do run often because of the health benefits. I’ve always thought the right way to run was to land on my heel and then transfer the weight to the ball of my foot, and finally the toes.  Now according to this article and this site I may have been doing it wrong.

When I first learned how to exist on UNIX, in 1988, I used vi as my primary editor. During the next nine years I taught myself how to become a power user - migrating from the simple motion and copy and paste to more complex skills like marks and named registers. When I started graduate school I saw many of the professors and grad students using emacs.  I tried it out a couple of times, but it was not until 1997 that I decided to take the time to stick with emacs and take the time to learn the right way to do things even when I could get the job done faster in vi.

I’m trying to formulate a sensible strategy to overhaul my net presence. The rough plan so far:

• Change my 12-year-old email address that is on every spammer’s short list
•  Extract friends’ contact info from Facebook
• Delete Facebook account.
• Import FB contacts into Google & Mac
• Redirect facebook friends to current tech blog (aijazansari.com) and new personal blog.
• Find out if FB friends can subscribe to an RSS feed of my blog somehow (doesn’t seem possible any more)
• Pick up the phone and actually talk to friends more often.

The goal’s pretty obvious - I want to reclaim my data.  I think I own my relationships, not FB, not Twitter, and not Google+.  So far, G+ may be the most accommodating network out there - if I can export my G+ presence as easily as I can export my G+ contacts, we might have a good candidate here.

If you have any ideas or comments or experience with this, please let me know.

I’ll keep you posted.

Glen Ellyn Volunteer Fire Company

Fire marks were used in the 1700s to designate homes or buildings protected by the fire insurance companies. They were generally oval plates placed on the outside of a structure to let volunteer fire brigades know which buildings carried a “reward” if saved.

You can read more on this here.

I hadn’t really given much thought to how the iPhone handles scrolling until I recently had to implement it myself. I needed to add vertical scrolling to a UIView that models a real-life metaphor. In my particular case I feel using a UIScrollView would break the metaphor - the user would “snap out” of the immersive app and realize they’re merely using an iPhone app with a pretty skin. So the natural solution was to implement scrolling myself. This is how it went from simple, unnatural scrolling to its current state of acceptable inertial scrolling.

Hello World on the iPhone

Yesterday I started learning how to write applications for the iPad and the iPhone.  There are so many books that promise to teach you everything you need to know that picking one or two (or three) can be very difficult.  While I normally like to learn new skills by reading a good book, I think for iOS development a more dynamic source would be a better choice.

When I recently switched from the iPhone to HTC Evo running Android, I found the Evo’s Alarm Clock app surprisingly primitive.  When I had multiple alarms set, it wouldn’t sort them by the time of day.  Predictably, I started looking for alarm clock apps online, but the others were even more primitive.  One was so bad that once the alarm went off, there was no way to turn it off other than rebooting the phone.