use stdout of a process as a command in bash-CodePudding

I have a rust script that prints something with a newline character at the end. I would like that line to be launched in bash instead of only being printed out. It acts as:

echo "my_line"

while I just want

my_line

as I would type it regularly in a terminal.

How would one achieve this and would it also be possible for a backgrounded process without a terminal open?

CodePudding user response：

You need

$(echo "my_line")

to execute the command after command substitution. Check https://www.gnu.org/software/bash/manual/html_node/Command-Substitution.html.

CodePudding user response：

You should use command substitution if possible, but there are times when you need things to be interpreted by the shell instead, like conditionals, redirects, or shell variables (cmd1 && cmd2, cmd > file, $var). If that is the case, then you should create a subprocess in Rust. This will spawn Bash, then tell it to run whatever is in command_string. Note that the command string parameter is a single string, and should not be split into vectored args:

use std::process::Command;
use std::thread;

fn main() {
    let command_string = "sleep 3 && echo done";

    let out = Command::new("bash")
        .args(["-c", command_string])
        .output()
        .expect("failed to run command")
        .stdout;
    println!("{}", String::from_utf8(out).unwrap());
}