Write a Shell in C (2015)

If you want to see a pretty complete shell in a higher level language (Python, 11K lines of code), check out: https://github.com/oilshell/oil/ And a blog here: http://www.oilshell.org/ (index: http://www.oilshell.org/blog/2016/11/20.html) This article is good in that it shows that starting processes boils down to the system calls fork(), exec(), wait(), etc. My shell has function calls, loops, conditionals, pipelines, subshells, command substitution, redirects, here docs, etc. (The code has some messiness, but the…

For anybody who's wondering why I chose to post this: I found this while Googling around trying to answer the question "how hard is it to write a custom shell, and how would you get started?" The reason I wanted to know that is this: I've always been intrigued by the idea of making "things" ( hand-waving around the details of what that means) available via ssh. Imagine something like a MUD, except not a MUD exactly. Just the idea…

Honestly this was one of the most influential pieces of writing I've ever read. Back in the day this opened up a lot of the implementation details on interpreters and C for me. It quite literally helped "get" how programs are designed and written. I found this piece around eighth grade and I'm very glad I did! :-)