Struct std::process::Stdio

pub struct Stdio(_);

Describes what to do with a standard I/O stream for a child process when passed to the stdin, stdout, and stderr methods of Command.

Methods

impl Stdio

pub fn piped() -> Stdio

A new pipe should be arranged to connect the parent and child processes.

Examples

With stdout:

use std::process::{Command, Stdio};

let output = Command::new("echo")
    .arg("Hello, world!")
    .stdout(Stdio::piped())
    .output()
    .expect("Failed to execute command");

assert_eq!(String::from_utf8_lossy(&output.stdout), "Hello, world!\n");
// Nothing echoed to console

With stdin:

use std::io::Write;
use std::process::{Command, Stdio};

let mut child = Command::new("rev")
    .stdin(Stdio::piped())
    .stdout(Stdio::piped())
    .spawn()
    .expect("Failed to spawn child process");

{
    let mut stdin = child.stdin.as_mut().expect("Failed to open stdin");
    stdin.write_all("Hello, world!".as_bytes()).expect("Failed to write to stdin");
}

let output = child.wait_with_output().expect("Failed to read stdout");
assert_eq!(String::from_utf8_lossy(&output.stdout), "!dlrow ,olleH\n");

pub fn inherit() -> Stdio

The child inherits from the corresponding parent descriptor.

Examples

With stdout:

use std::process::{Command, Stdio};

let output = Command::new("echo")
    .arg("Hello, world!")
    .stdout(Stdio::inherit())
    .output()
    .expect("Failed to execute command");

assert_eq!(String::from_utf8_lossy(&output.stdout), "");
// "Hello, world!" echoed to console

With stdin:

use std::process::{Command, Stdio};

let output = Command::new("rev")
    .stdin(Stdio::inherit())
    .stdout(Stdio::piped())
    .output()
    .expect("Failed to execute command");

println!("You piped in the reverse of: {}", String::from_utf8_lossy(&output.stdout));

pub fn null() -> Stdio

This stream will be ignored. This is the equivalent of attaching the stream to /dev/null

Examples

With stdout:

use std::process::{Command, Stdio};

let output = Command::new("echo")
    .arg("Hello, world!")
    .stdout(Stdio::null())
    .output()
    .expect("Failed to execute command");

assert_eq!(String::from_utf8_lossy(&output.stdout), "");
// Nothing echoed to console

With stdin:

use std::process::{Command, Stdio};

let output = Command::new("rev")
    .stdin(Stdio::null())
    .stdout(Stdio::piped())
    .output()
    .expect("Failed to execute command");

assert_eq!(String::from_utf8_lossy(&output.stdout), "");
// Ignores any piped-in input

Trait Implementations

impl Debug for Stdio

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.

impl From<ChildStdin> for Stdio

fn from(child: ChildStdin) -> Stdio

Performs the conversion.

impl From<ChildStdout> for Stdio

fn from(child: ChildStdout) -> Stdio

Performs the conversion.

impl From<ChildStderr> for Stdio

fn from(child: ChildStderr) -> Stdio

Performs the conversion.

impl From<File> for Stdio

fn from(file: File) -> Stdio

Performs the conversion.

impl FromRawFd for Stdio

unsafe fn from_raw_fd(fd: RawFd) -> Stdio

This is supported on Unix only.

Constructs a new instance of Self from the given raw file descriptor.

impl FromRawHandle for Stdio

unsafe fn from_raw_handle(handle: RawHandle) -> Stdio

This is supported on Windows only.

Constructs a new I/O object from the specified raw handle.