std::process::Command - Rust
Description: API documentation for the Rust `Command` struct in crate `std`.
Keywords: rust, rustlang, rust-lang, Command

# Struct std::process::Command 1.0.0 [−] [src]

    pub struct Command { /* fields omitted */ }

A process builder, providing fine-grained control over how a new process should be spawned.

A default configuration can be generated using `Command::new(program)`, where `program` gives a path to the program to be executed. Additional builder methods allow the configuration to be changed (for example, by adding arguments) prior to spawning:

    use std::process::Command;

    let output = if cfg!(target_os = "windows") {
        Command::new("cmd")
                .args(&["/C", "echo hello"])
                .output()
                .expect("failed to execute process")
    } else {
        Command::new("sh")
                .arg("-c")
                .arg("echo hello")
                .output()
                .expect("failed to execute process")
    };

    let hello = output.stdout;Run

## Methods

### `impl Command`
[src]

#### `pub fn new<S: AsRef<OsStr>>(program: S) -> Command`
[src]

Constructs a new `Command` for launching the program at path `program`, with the following default configuration:

- No arguments to the program
- Inherit the current process's environment
- Inherit the current process's working directory
- Inherit stdin/stdout/stderr for `spawn` or `status`, but create pipes for `output`

Builder methods are provided to change these defaults and otherwise configure the process.

If `program` is not an absolute path, the `PATH` will be searched in an OS-defined way.

The search path to be used may be controlled by setting the `PATH` environment variable on the Command, but this has some implementation limitations on Windows (see https://github.com/rust-lang/rust/issues/37519).

# Examples

Basic usage:

    use std::process::Command;

    Command::new("sh")
            .spawn()
            .expect("sh command failed to start");Run

#### `pub fn arg<S: AsRef<OsStr>>(&mut self, arg: S) -> &mut Command`
[src]

Add an argument to pass to the program.

Only one argument can be passed per use. So instead of:

    .arg("-C /path/to/repo")Run

usage would be:

    .arg("-C")
    .arg("/path/to/repo")Run

To pass multiple arguments see `args`.

# Examples

Basic usage:

    use std::process::Command;

    Command::new("ls")
            .arg("-l")
            .arg("-a")
            .spawn()
            .expect("ls command failed to start");Run

#### `pub fn args<I, S>(&mut self, args: I) -> &mut Command where
I: IntoIterator<Item = S>,
S: AsRef<OsStr>,`
[src]

Add multiple arguments to pass to the program.

To pass a single argument see `arg`.

# Examples

Basic usage:

    use std::process::Command;

    Command::new("ls")
            .args(&["-l", "-a"])
            .spawn()
            .expect("ls command failed to start");Run

#### `pub fn env<K, V>(&mut self, key: K, val: V) -> &mut Command where
K: AsRef<OsStr>,
V: AsRef<OsStr>,`
[src]

Inserts or updates an environment variable mapping.

Note that environment variable names are case-insensitive (but case-preserving) on Windows, and case-sensitive on all other platforms.

# Examples

Basic usage:

    use std::process::Command;

    Command::new("ls")
            .env("PATH", "/bin")
            .spawn()
            .expect("ls command failed to start");Run

#### `pub fn envs<I, K, V>(&mut self, vars: I) -> &mut Command where
I: IntoIterator<Item = (K, V)>,
K: AsRef<OsStr>,
V: AsRef<OsStr>,`
1.19.0
[src]

Add or update multiple environment variable mappings.

# Examples

Basic usage:

    use std::process::{Command, Stdio};
    use std::env;
    use std::collections::HashMap;

    let filtered_env : HashMap<String, String> =
        env::vars().filter(|&(ref k, _)|
            k == "TERM" || k == "TZ" || k == "LANG" || k == "PATH"
        ).collect();

    Command::new("printenv")
            .stdin(Stdio::null())
            .stdout(Stdio::inherit())
            .env_clear()
            .envs(&filtered_env)
            .spawn()
            .expect("printenv failed to start");Run

#### `pub fn env_remove<K: AsRef<OsStr>>(&mut self, key: K) -> &mut Command`
[src]

Removes an environment variable mapping.

# Examples

Basic usage:

    use std::process::Command;

    Command::new("ls")
            .env_remove("PATH")
            .spawn()
            .expect("ls command failed to start");Run

#### `pub fn env_clear(&mut self) -> &mut Command`
[src]

Clears the entire environment map for the child process.

# Examples

Basic usage:

    use std::process::Command;

    Command::new("ls")
            .env_clear()
            .spawn()
            .expect("ls command failed to start");Run

#### `pub fn current_dir<P: AsRef<Path>>(&mut self, dir: P) -> &mut Command`
[src]

Sets the working directory for the child process.

# Examples

Basic usage:

    use std::process::Command;

    Command::new("ls")
            .current_dir("/bin")
            .spawn()
            .expect("ls command failed to start");Run

#### `pub fn stdin<T: Into<Stdio>>(&mut self, cfg: T) -> &mut Command`
[src]

Configuration for the child process's standard input (stdin) handle.

# Examples

Basic usage:

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

    Command::new("ls")
            .stdin(Stdio::null())
            .spawn()
            .expect("ls command failed to start");Run

#### `pub fn stdout<T: Into<Stdio>>(&mut self, cfg: T) -> &mut Command`
[src]

Configuration for the child process's standard output (stdout) handle.

# Examples

Basic usage:

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

    Command::new("ls")
            .stdout(Stdio::null())
            .spawn()
            .expect("ls command failed to start");Run

#### `pub fn stderr<T: Into<Stdio>>(&mut self, cfg: T) -> &mut Command`
[src]

Configuration for the child process's standard error (stderr) handle.

# Examples

Basic usage:

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

    Command::new("ls")
            .stderr(Stdio::null())
            .spawn()
            .expect("ls command failed to start");Run

#### `pub fn spawn(&mut self) -> Result<Child>`
[src]

Executes the command as a child process, returning a handle to it.

By default, stdin, stdout and stderr are inherited from the parent.

# Examples

Basic usage:

    use std::process::Command;

    Command::new("ls")
            .spawn()
            .expect("ls command failed to start");Run

#### `pub fn output(&mut self) -> Result<Output>`
[src]

Executes the command as a child process, waiting for it to finish and collecting all of its output.

By default, stdin, stdout and stderr are captured (and used to provide the resulting output).

# Examples

    use std::process::Command;
    let output = Command::new("/bin/cat")
                         .arg("file.txt")
                         .output()
                         .expect("failed to execute process");

    println!("status: {}", output.status);
    println!("stdout: {}", String::from_utf8_lossy(&output.stdout));
    println!("stderr: {}", String::from_utf8_lossy(&output.stderr));

    assert!(output.status.success());Run

#### `pub fn status(&mut self) -> Result<ExitStatus>`
[src]

Executes a command as a child process, waiting for it to finish and collecting its exit status.

By default, stdin, stdout and stderr are inherited from the parent.

# Examples

    use std::process::Command;

    let status = Command::new("/bin/cat")
                         .arg("file.txt")
                         .status()
                         .expect("failed to execute process");

    println!("process exited with: {}", status);

    assert!(status.success());Run

## Trait Implementations

### `impl Debug for Command`
[src]

#### `fn fmt(&self, f: &mut Formatter) -> Result`
[src]

Format the program and arguments of a Command for display. Any non-utf8 data is lossily converted using the utf8 replacement character.

### `impl CommandExt for Command`
[src]

#### `fn uid(&mut self, id: u32) -> &mut Command`
[src]

This is supported on Unix only.

Sets the child process's user id. This translates to a `setuid` call in the child process. Failure in the `setuid` call will cause the spawn to fail. Read more

#### `fn gid(&mut self, id: u32) -> &mut Command`
[src]

This is supported on Unix only.

Similar to `uid`, but sets the group id of the child process. This has the same semantics as the `uid` field. Read more

#### `fn before_exec<F>(&mut self, f: F) -> &mut Command where
F: FnMut() -> Result<()> + Send + Sync + 'static,`
[src]

This is supported on Unix only.

Schedules a closure to be run just before the `exec` function is invoked. Read more

#### `fn exec(&mut self) -> Error`
[src]

This is supported on Unix only.

Performs all the required setup by this `Command`, followed by calling the `execvp` syscall. Read more

### `impl CommandExt for Command`
1.16.0
[src]

#### `fn creation_flags(&mut self, flags: u32) -> &mut Command`
[src]

This is supported on Windows only.

Sets the [process creation flags][1] to be passed to `CreateProcess`. Read more

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