Crate subprocess

Execution and interaction with external processes.

The entry point to the module is the Popen struct and the Exec builder class. Popen is modeled after Python's subprocess.Popen, with modifications to make it fit to Rust, while Exec provides a nice Rustic builder-style API with convenient methods for streaming and capturing of output, as well as combining Popen instances into pipelines.

Compared to std::process, the module follows the following additional features:

• The communicate method for deadlock-free reading of subprocess output/error, while simultaneously providing it stdin.

• Advanced redirection options, such as connecting standard streams to arbitary files, or merging errors into output like shell's 2>&1 operator.

• Non-blocking and timeout methods to wait on the process: poll, wait, and wait_timeout.

• Connecting multiple commands into OS-level pipelines.

Examples

Create Popen directly in order to communicate with a process and optionally terminate it:

let mut p = Popen::create(&["ps", "x"], PopenConfig {
    stdout: Redirection::Pipe, ..Default::default()
})?;

// Since we requested stdout to be redirected to a pipe, the parent's
// end of the pipe is available as p.stdout.  It can either be read
// directly, or processed using the communicate() method:
let (out, err) = p.communicate(None)?;

// check if the process is still alive
if let Some(exit_status) = p.poll() {
    // the process has finished
} else {
    // it is still running, terminate it
    p.terminate()?;
}

Use the Exec builder to execute a command and capture its output:

let dir_checksum = {
    Exec::cmd("find . -type f") | Exec::cmd("sort") | Exec::cmd("sha1sum")
}.capture()?.output_str();

Structs

Exec	A builder for Popen instances, providing control and convenience methods.
NullFile	Marker value for stdin, stdout, and stderr methods of Exec and Pipeline.
Pipeline	A builder for multiple Popen instances connected via pipes.
Popen	Interface to a running subprocess.
PopenConfig	Structure designed to be passed to Popen::create.

Enums

ExitStatus	Exit status of a process.
PopenError	Error in Popen calls.
Redirection	Instruction what to do with a stream in the child process.

Type Definitions

Result

Result type for the subprocess calls.