Sometimes developers use a flag or option that looks logical to them, but they do not fully understand it. It could even work in a particular situation but fail miserably under different circumstances. Let me explain what I mean.

At the company where I work, we typically ask candidates to do a test task. The task is very simple, and the algorithm is well known and clearly explained in 1973. For a good developer, it will take half a day. Maybe even less. The final part of that task is to copy lines from many smaller files into one big one. The smaller files are typically around 100 Mb in size.

Several days ago I got the test task from