I wrote this blog post to document my process of building a simple shell using Rust. I learned a lot about how shells, terminal emulators, and the OS interact by going through this exercise, so I hope this is useful to others as well.
Feel free to reach out if you have any questions.
If you really want job control, a path, environmental variables, and all the things that make a shell a shell, you have to be using exec() or execvp() https://doc.rust-lang.org/std/process/struct.Command.html#me... . Otherwise all you've done is wrap an existing shell that does all the work for you, and that was an immediate fail when we had to a make a shell in my undergrad systems course.
An easy check is the use the command "echo $SHELL". If that spits out anything besides literally "$SHELL", you're farming out.
All that said, Rust's exec() is listed a unix specific, so if you're on Windows, I guess you're stuck.
I created a demo in the Rust playground [0] which shows that there is no implicit environment variable expansion. Also, the source for `std::process:Command` [1] looks to be calling into libc to perform a fork/exec.
That said, this is rather new territory for me, so let me know if I'm missing something here.
[0] : https://play.rust-lang.org/?version=stable&mode=debug&editio... [1] : https://github.com/rust-lang/rust/blob/master/src/libstd/sys...
All of this is of course Unix specific, on Windows it uses `CreateProcess`.
This could be by adding some text to clarify that this doesn’t use a shell, or maybe changing the examples to not imply one is used. It just depends.