"The power of imagination makes us infinite." - John Muir

Welcome to rozmichelle.com!

On this site, you will find all kinds of creative outlets, with topics including poetry, travel, design, and development. I like to think of my site as a diverse representation of me as I strive to master self-understanding. I started this website in 2005 and it continues to be a source of expression for me as I design, write, cook, and code my way through life. I hope you enjoy the journey!

Thank you so much for being here, and please sign my guestbook or send me a message if you are inspired by this site in any way.

Pipes, Forks, & Dups: Understanding Command Execution and Input/Output Data Flow

I'm currently enrolled in a systems programming class at Stanford (CS110: Principles of Computer Systems). It is the second systems class I've taken (the first was CS107 which teaches C and focuses on understanding pointers and memory management). This class focuses mainly on the inner workings of the operating system, using C and C++ to teach us concepts like process management, program execution, and handling data. While I enjoyed and quickly grasped the concepts taught in CS107, I've had a harder time understanding the material in CS110. The class itself is extremely interesting and well-taught, but my main pain point has been understanding the way processes share data and how input and output work across commands entered in the terminal. In the last few days, however, I finally found clarity when I started creating diagrams to model process behavior and the path that data takes as it travels from one command to another. I'd like to share what I've learned with you. In this post, we'll go over how Unix commands pass data to each other via pipes and input/output redirection and I'll illustrate what actually happens to the flow of data when a command is executed.