Command in std::process - Rust (original) (raw)

pub struct Command { /* private fields */ }

Expand description

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;

Command can be reused to spawn multiple processes. The builder methods change the command without needing to immediately spawn the process.

use std::process::Command;

let mut echo_hello = Command::new("sh");
echo_hello.arg("-c")
          .arg("echo hello");
let hello_1 = echo_hello.output().expect("failed to execute process");
let hello_2 = echo_hello.output().expect("failed to execute process");

Similarly, you can call builder methods after spawning a process and then spawn a new process with the modified settings.

use std::process::Command;

let mut list_dir = Command::new("ls");

// Execute `ls` in the current directory of the program.
list_dir.status().expect("process failed to execute");

println!();

// Change `ls` to execute in the root directory.
list_dir.current_dir("/");

// And then execute `ls` again but in the root directory.
list_dir.status().expect("process failed to execute");

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 thePATH environment variable on the Command, but this has some implementation limitations on Windows (see issue #37519).

Basic usage:

use std::process::Command;

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

Adds an argument to pass to the program.

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

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

usage would be:

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

To pass multiple arguments see args.

Note that the argument is not passed through a shell, but given literally to the program. This means that shell syntax like quotes, escaped characters, word splitting, glob patterns, substitution, etc. have no effect.

Basic usage:

use std::process::Command;

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

Adds multiple arguments to pass to the program.

To pass a single argument see arg.

Note that the arguments are not passed through a shell, but given literally to the program. This means that shell syntax like quotes, escaped characters, word splitting, glob patterns, substitution, etc. have no effect.

Basic usage:

use std::process::Command;

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

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.

Basic usage:

use std::process::Command;

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

Adds or updates multiple environment variable mappings.

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");

Removes an environment variable mapping.

Basic usage:

use std::process::Command;

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

Clears the entire environment map for the child process.

Basic usage:

use std::process::Command;

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

Sets the working directory for the child process.

If the program path is relative (e.g., "./script.sh"), it’s ambiguous whether it should be interpreted relative to the parent’s working directory or relative to current_dir. The behavior in this case is platform specific and unstable, and it’s recommended to usecanonicalize to get an absolute program path instead.

Basic usage:

use std::process::Command;

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

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

Defaults to inherit when used with spawn or status, and defaults to piped when used with output.

Basic usage:

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

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

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

Defaults to inherit when used with spawn or status, and defaults to piped when used with output.

Basic usage:

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

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

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

Defaults to inherit when used with spawn or status, and defaults to piped when used with output.

Basic usage:

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

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

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

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

Basic usage:

use std::process::Command;

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

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

By default, stdout and stderr are captured (and used to provide the resulting output). Stdin is not inherited from the parent and any attempt by the child process to read from the stdin stream will result in the stream immediately closing.

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

println!("status: {}", output.status);
io::stdout().write_all(&output.stdout).unwrap();
io::stderr().write_all(&output.stderr).unwrap();

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

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

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

use std::process::Command;

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

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

assert!(status.success());

Returns the path to the program that was given to Command::new.

use std::process::Command;

let cmd = Command::new("echo");
assert_eq!(cmd.get_program(), "echo");

Returns an iterator of the arguments that will be passed to the program.

This does not include the path to the program as the first argument; it only includes the arguments specified with Command::arg andCommand::args.

use std::ffi::OsStr;
use std::process::Command;

let mut cmd = Command::new("echo");
cmd.arg("first").arg("second");
let args: Vec<&OsStr> = cmd.get_args().collect();
assert_eq!(args, &["first", "second"]);

Returns an iterator of the environment variables that will be set when the process is spawned.

Each element is a tuple (&OsStr, Option<&OsStr>), where the first value is the key, and the second is the value, which is None if the environment variable is to be explicitly removed.

This only includes environment variables explicitly set withCommand::env, Command::envs, and Command::env_remove. It does not include environment variables that will be inherited by the child process.

use std::ffi::OsStr;
use std::process::Command;

let mut cmd = Command::new("ls");
cmd.env("TERM", "dumb").env_remove("TZ");
let envs: Vec<(&OsStr, Option<&OsStr>)> = cmd.get_envs().collect();
assert_eq!(envs, &[
    (OsStr::new("TERM"), Some(OsStr::new("dumb"))),
    (OsStr::new("TZ"), None)
]);

Returns the working directory for the child process.

This returns None if the working directory will not be changed.

use std::path::Path;
use std::process::Command;

let mut cmd = Command::new("ls");
assert_eq!(cmd.get_current_dir(), None);
cmd.current_dir("/bin");
assert_eq!(cmd.get_current_dir(), Some(Path::new("/bin")));

Sets the child process’s user ID. This translates to asetuid call in the child process. Failure in the setuidcall will cause the spawn to fail. Read more

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

🔬 This is a nightly-only experimental API. (setgroups #90747)

Sets the supplementary group IDs for the calling process. Translates to a setgroups call in the child process. Read more

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

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

👎 Deprecated since 1.37.0:

should be unsafe, use pre_exec instead

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

🔬 This is a nightly-only experimental API. (linux_pidfd #82971)

Sets whether a PidFd should be created for the Childspawned by this Command. By default, no pidfd will be created. Read more

🔬 This is a nightly-only experimental API. (windows_process_extensions_force_quotes #82227)

Forces all arguments to be wrapped in quote (") characters. Read more

🔬 This is a nightly-only experimental API. (windows_process_extensions_raw_arg #29494)

Append literal text to the command line without any quoting or escaping. Read more

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

impl Any for T where

T: 'static + ?Sized,

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

impl From for T

impl<T, U> Into for T where

U: From,

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.