How to Practice Unix Programming in C?

Question

After five years of professional Java (and to a lesser extent, Python) programming and slowly feeling my CS education slip away, I decided I wanted to broaden my horizons / general usefulness to the world and do something that feels more (to me) like I really have an influence over the machine. I chose to learn C and Unix programming since I feel like that is where many of the most interesting problems are.

My end goal is to be able to do this professionally, if for no other reason than the fact that I have to spend 40-50 hours per week on work that pays the bills, so it may as well also be the type of coding I want to get better at. Of course, you don't get hired to do things you haven't dont before, so for now I am ramping up on my own.

To this end, I started with K&R, which was a great resource in part due to the exercises spread throughout each chapter. After that I moved on to Computer Systems: A Programmer's Perspective, followed by ten chapters of Advanced Programming in the Unix Environment. When I am done with this book, I will read Unix Network Programming.

What I'm missing in the Stevens books is the lack of programming problems; they mainly document functionality and provide examples, with a few end-of-chapter questions following. I feel that I would benefit much more from being challenged to use the knowledge in each chapter ala K&R. I could write some test program for each function, but this is a less desirable method as (1) I would probably be less motivated than if I were rising to some external challenge, and (2) I will naturally only think to use the function in the ways that have already occurred to me.

So, I'd like to get some recommendations on how to practice. Obviously, my first choice would be to find some resource that has Unix programming challenges. I have also considered finding and attempting to contribute to some open source C project, but this is a bit daunting as there would be some overhead in learning to use the software, then learning the codebase. The only open-source C project I can think of that I use regularly is Python, and I'm not sure how easy that would be to get started on.

That said, I'm open to all kinds of suggestions as there are likely things I haven't even thought of.

Answer 1

Reinvent a lot of the core Unix utilities. Most of these were (and still are) written in C, so they are a good way to start off learning. Depending on your skill, pick harder or easier utilities to copy.

Try writing your own malloc. You'll learn a lot about Unix and a lot of C programming as well.

Google for CS operating system courses and do the projects there. Many schools have these projects on public websites so you could get everything you need. Here is a link to Purdue's site. Give the shell project a shot, it was difficult but really educational.

Answer 2

Here are a few stackoverflow postings discussing C/Unix programming books. Their main claim to fame is extensive fan-out to other resources.

Practice some of the idioms (understand the ins and outs of pointers etc) and pick projects that help with that. The third item in the list has an answer (disclaimer, I wrote it) with a bunch of high-level C idioms where an idiomatic C program would differ from Java.

Learning XLib or Win32 GUI programming with C is probably less useful as almost anything is better than C for GUI programming and wrapping a core C engine with another language is generally much easier - unless you're really concerned with speed. As a starting point, concentrate on 'systems' programming applications, which is where you are most likely to get real mileage from C. Learn how the C interface of one of the scripting languages like Tcl or Python works.

Writing some bit-twiddly and pointer heavy code (e.g. picking apart network packets or interpreting a protocol), or server-side items using sockets will take you right into C's core competencies. If you've got some of the WRS books, try making pthreads work (IIRC UNP2 has a big section about pThreads). For a contrast, write something that uses non-blocking I/O. This stuff is C's home turf and you'll get a good working knowledge of C by doing this. Troll through the RFCs for some ideas of network protocols to implement.

• What are good Linux/Unix books for an advancing user?
• What are some good resources for learning C beyond K&R
• Resources for learning C program design
• What’s a good way to start learning about Data Structures & Algorithms?
• Algorithms in C

Answer 3

The best way to consolidate your learnings it to practise. So just choose a kind of application that interest you and start developing it (ex. a network cli/server simple app). Try to test the most of unix API (files, sockets, etc.) to see how it works. You could for example get an unix programming book, follow its chapters and test on your application everything you read, by creating your own functions. On that way, you can start to develop your own function library to be used in further projects.

Answer 4

Write a webserver.

• Make it multi-threaded.

• Have it support a new scripting language you develop (a la PHP, etc.)

• Allow uploads from authenticated users.

• Write a plugin for your favorite tool (ie. integrate with SVN to give a webview).

Answer 5

Are you open to book suggestions? Although it is a bit dated (where "a bit" perhaps is a huge understatement), Maurice Bach's "The Design of the Unix Operating System" is a great book. It belongs next to K&R on your bookshelf.

Answer 6

You might try working your way through all the examples in the book Software Tools (Amazon). Much of it is pretty pedestrian (right-justify text, de-tabify, etc) but it's a great introduction to the unix philosophy and basic C programming.