In the video I teach the grep command. The material comes from the beginning of the lesson Finding Things, section 7 of the Unix Shell tutorial. I selected this topic because it is self-contained and can be presented coherently in 3 minutes.
Watching the video afterwards I realised with some dismay that I am repeatedly making the mistake of saying I am searching for one thing, while my shell command actually shows me searching for something else. I can only hope this was caused by my nervousness when making this video, and that I don’t make that kind of switch habitually when I teach.
I used Camtasia for the recording (the free trial version) and it worked very well. Editing the video afterwards was a breeze, and I could easily remove the awkward pauses at the beginning and the end. That’s why the video is slightly shorter than 3 minutes.