This works well as a learning method, most probably because UNIX tools are well documented, and there are readily available binaries. Many introductory programm

This works well as a learning method, most probably because UNIX tools are well documented, and there are readily available binaries. Many introductory programming courses I took and taught back in the day were using UNIX tools as programming assignments. I believe, any well documented coding problem accompanied with a sample binary implementation should have the effective educational value. Sites like interviewstreet.com should take this as a guide, even though their audience is not beginners. If you look at sample problems there, they are usually poorly described, and sample outputs are trivial and don't contribute to the textual description.