如何获取从 Rust 程序内部运行的 Bash 脚本的退出代码？

Question

I've been trying to wrap my head around a few simple implementations of systems programming involving the ability to call Bash from C and Rust. I was curious if there was a way to modify the following statement, in Rust specifically, to allow me to get a return value of 4 from a Bash script that runs in the following manner:

let status = Command::new("pathtoscript").status().expect("failed to execute process");

Rust String stuff confuses me initially, but any combination of actions that leads to status granting me access to the value of 4 being returned to the parent process would be great . Thank you so much in advance for helping me. I have checked the Rust documentation but I haven't found anything for getting things BACK to the parent process, only to the child process.

I should say it goes without saying for my application writing to a file and reading from that file is not sufficient or secure enough.

Answer 1

If you need the exit code 4 use status.code() :

use std::process::Command;

fn main() {
    let status = Command::new("./script.sh")
        .status()
        .expect("failed to execute process");
    println!("{}", status.code().unwrap()); // 4
}

My script.sh file:

#!/bin/bash

# Will exit with status of last command.
# exit $?
# echo $?

# Will return 4 to shell.
exit 4

---

And see this too:

use std::process::Command;

let status = Command::new("mkdir")
                     .arg("projects")
                     .status()
                     .expect("failed to execute mkdir");

match status.code() {
    Some(code) => println!("Exited with status code: {}", code),
    None       => println!("Process terminated by signal")
}