Struct Command

pub struct Command { /* private fields */ }

The product of a PlatformRef::prepare_external_driver() operation.

This type allows to creation of std::process::Command, ready to run, with stderr and stdout set to inherit, but stdin closed. It’s expected to leave its result in the file substituted at current which is then supposed to be read back from there.

Implementations

impl Command

pub fn open_result_file(&self) -> Result<File>

Open the file which should have been written to the location of ours, to yield the result of the merge operation. Calling this makes sense only after the merge command has finished successfully.

Methods from Deref<Target = Command>

pub fn arg<S>(&mut self, arg: S) -> &mut Command

where S: AsRef<OsStr>,

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, variable substitution, etc. have no effect.

On Windows, use caution with untrusted inputs. Most applications use the standard convention for decoding arguments passed to them. These are safe to use with arg. However, some applications such as cmd.exe and .bat files use a non-standard way of decoding arguments. They are therefore vulnerable to malicious input.

In the case of cmd.exe this is especially important because a malicious argument can potentially run arbitrary shell commands.

See Windows argument splitting for more details or raw_arg for manually implementing non-standard argument encoding.

Examples

use std::process::Command;

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

pub fn args<I, S>(&mut self, args: I) -> &mut Command

where I: IntoIterator<Item = S>, S: AsRef<OsStr>,

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, variable substitution, etc. have no effect.

On Windows, use caution with untrusted inputs. Most applications use the standard convention for decoding arguments passed to them. These are safe to use with arg. However, some applications such as cmd.exe and .bat files use a non-standard way of decoding arguments. They are therefore vulnerable to malicious input.

In the case of cmd.exe this is especially important because a malicious argument can potentially run arbitrary shell commands.

See Windows argument splitting for more details or raw_arg for manually implementing non-standard argument encoding.

Examples

use std::process::Command;

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

pub fn env<K, V>(&mut self, key: K, val: V) -> &mut Command

where K: AsRef<OsStr>, V: AsRef<OsStr>,

Inserts or updates an explicit environment variable mapping.

This method allows you to add an environment variable mapping to the spawned process or overwrite a previously set value. You can use Command::envs to set multiple environment variables simultaneously.

Child processes will inherit environment variables from their parent process by default. Environment variables explicitly set using Command::env take precedence over inherited variables. You can disable environment variable inheritance entirely using Command::env_clear or for a single key using Command::env_remove.

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

Examples

use std::process::Command;

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

pub fn envs<I, K, V>(&mut self, vars: I) -> &mut Command

where I: IntoIterator<Item = (K, V)>, K: AsRef<OsStr>, V: AsRef<OsStr>,

Inserts or updates multiple explicit environment variable mappings.

This method allows you to add multiple environment variable mappings to the spawned process or overwrite previously set values. You can use Command::env to set a single environment variable.

Child processes will inherit environment variables from their parent process by default. Environment variables explicitly set using Command::envs take precedence over inherited variables. You can disable environment variable inheritance entirely using Command::env_clear or for a single key using Command::env_remove.

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

Examples

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");

pub fn env_remove<K>(&mut self, key: K) -> &mut Command

where K: AsRef<OsStr>,

Removes an explicitly set environment variable and prevents inheriting it from a parent process.

This method will remove the explicit value of an environment variable set via Command::env or Command::envs. In addition, it will prevent the spawned child process from inheriting that environment variable from its parent process.

After calling Command::env_remove, the value associated with its key from Command::get_envs will be None.

To clear all explicitly set environment variables and disable all environment variable inheritance, you can use Command::env_clear.

Examples

use std::process::Command;

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

pub fn env_clear(&mut self) -> &mut Command

Clears all explicitly set environment variables and prevents inheriting any parent process environment variables.

This method will remove all explicitly added environment variables set via Command::env or Command::envs. In addition, it will prevent the spawned child process from inheriting any environment variable from its parent process.

After calling Command::env_clear, the iterator from Command::get_envs will be empty.

You can use Command::env_remove to clear a single mapping.

Examples

use std::process::Command;

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

pub fn current_dir<P>(&mut self, dir: P) -> &mut Command

where P: AsRef<Path>,

Sets the working directory for the child process.

Platform-specific behavior

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 use canonicalize to get an absolute program path instead.

Examples

use std::process::Command;

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

pub fn stdin<T>(&mut self, cfg: T) -> &mut Command

where T: Into<Stdio>,

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.

Examples

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

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

pub fn stdout<T>(&mut self, cfg: T) -> &mut Command

where T: Into<Stdio>,

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.

Examples

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

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

pub fn stderr<T>(&mut self, cfg: T) -> &mut Command

where T: Into<Stdio>,

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.

Examples

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

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

pub fn spawn(&mut self) -> Result<Child, Error>

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

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

Examples

use std::process::Command;

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

pub fn output(&mut self) -> Result<Output, Error>

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.

Examples

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());

pub fn status(&mut self) -> Result<ExitStatus, Error>

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.

Examples

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());

pub fn get_program(&self) -> &OsStr

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

Examples

use std::process::Command;

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

pub fn get_args(&self) -> CommandArgs<'_>

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 and Command::args.

Examples

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"]);

pub fn get_envs(&self) -> CommandEnvs<'_>

Returns an iterator of the environment variables explicitly set for the child process.

Environment variables explicitly set using Command::env, Command::envs, and Command::env_remove can be retrieved with this method.

Note that this output does not include environment variables inherited from the parent process.

Each element is a tuple key/value pair (&OsStr, Option<&OsStr>). A None value indicates its key was explicitly removed via Command::env_remove. The associated key for the None value will no longer inherit from its parent process.

An empty iterator can indicate that no explicit mappings were added or that Command::env_clear was called. After calling Command::env_clear, the child process will not inherit any environment variables from its parent process.

Examples

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)
]);

pub fn get_current_dir(&self) -> Option<&Path>

Returns the working directory for the child process.

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

Examples

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")));

Trait Implementations

impl Debug for Command

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

Formats the value using the given formatter.

impl Deref for Command

type Target = Command

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl DerefMut for Command

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.