io 0.3.1

  • Installing
  • Versions
  • 95

Contains utilities for the Dart VM's dart:io.

Build Status


NOTE: Due to the changing nature of the Dart SDK (towards 2.0.0), running dartfmt requires the local executable:

$ pub run dart_style:format

Usage - io.dart



Returns whether a provided file path is considered executable on the host operating system.



An enum-like class that contains known exit codes.


A higher-level service for spawning and communicating with processes.

Use spawn to create a process with std[in|out|err] forwarded by default
/// Runs `dartfmt` commands and `pub publish`.
Future<Null> main() async {
  final manager = new ProcessManager();
  // Runs dartfmt --version and outputs the result via stdout.
  print('Running dartfmt --version');
  var spawn = await manager.spawn('dartfmt', ['--version']);
  await spawn.exitCode;
  // Runs dartfmt -n . and outputs the result via stdout.
  print('Running dartfmt -n .');
  spawn = await manager.spawn('dartfmt', ['-n', '.']);
  await spawn.exitCode;
  // Runs pub publish. Upon hitting a blocking stdin state, you may directly
  // output to the processes's stdin via your own, similar to how a bash or
  // shell script would spawn a process.
  print('Running pub publish');
  spawn = await manager.spawn('pub', ['publish']);
  await spawn.exitCode;
  // Closes stdin for the entire program.
  await sharedStdIn.terminate();


A safer version of the default stdin stream from dart:io that allows a subscriber to cancel their subscription, and then allows a new subscriber to start listening. This differs from the default behavior where only a single listener is ever allowed in the application lifecycle:

test('should allow multiple subscribers', () async {
  final logs = <String>[];
  final asUtf8 = sharedStdIn.transform(UTF8.decoder);
  // Wait for input for the user.
  logs.add(await asUtf8.first);
  // Wait for more input for the user.
  logs.add(await asUtf8.first);
  expect(logs, ['Hello World', 'Goodbye World']);

For testing, an instance of SharedStdIn may be created directly.

Usage - ansi.dart

import 'dart:io' as io;
import 'package:io/ansi.dart';

void main() {
  // To use one style, call the `wrap` method on one of the provided top-level
  // values.
  io.stderr.writeln(red.wrap("Bad error!"));

  // To use multiple styles, call `wrapWith`.
  print(wrapWith('** Important **', [red, styleBold, styleUnderlined]));

  // The wrap functions will simply return the provided value unchanged if
  // `ansiOutputEnabled` is false.
  // You can override the value `ansiOutputEnabled` by wrapping code in
  // `overrideAnsiOutput`.
  overrideAnsiOutput(false, () {
    assert('Normal text' == green.wrap('Normal text'));


  • Added SharedStdIn.nextLine (similar to readLineSync) and lines:
main() async {
  // Prints the first line entered on stdin.
  print(await sharedStdIn.nextLine());
  // Prints all remaining lines.
  await for (final line in sharedStdIn.lines) {
  • Added a copyPath and copyPathSync function, similar to cp -R.

  • Added a dependency on package:path.

  • Added the remaining missing arguments to ProcessManager.spawnX which forward to Process.start. It is now an interchangeable function for running a process.


  • BREAKING CHANGE: The arguments argument to ProcessManager.spawn is now positional (not named) and required. This makes it more similar to the built-in Process.start, and easier to use as a drop in replacement:
main() {
  processManager.spawn('dart', ['--version']);
  • Fixed a bug where processes created from ProcessManager.spawn could not have their stdout/stderr read through their respective getters (a runtime error was always thrown).

  • Added ProcessMangaer#spawnBackground, which does not forward stdin.

  • Added ProcessManager#spawnDetached, which does not forward any I/O.

  • Added the shellSplit() function, which parses a list of arguments in the same manner as the POSIX shell.


  • Initial commit of...
    • FutureOr<bool> String isExecutable(path).
    • ExitCode
    • ProcessManager and Spawn
    • sharedStdIn and SharedStdIn
    • ansi.dart library with support for formatting terminal output

1. Depend on it

Add this to your package's pubspec.yaml file:

  io: "^0.3.1"

2. Install it

You can install packages from the command line:

with pub:

$ pub get

with Flutter:

$ flutter packages get

Alternatively, your editor might support pub get or packages get. Check the docs for your editor to learn more.

3. Import it

Now in your Dart code, you can use:

import 'package:io/io.dart';
Version Uploaded Documentation Archive
0.3.1 Dec 1, 2017 Go to the documentation of io 0.3.1 Download io 0.3.1 archive
0.3.0 Oct 12, 2017 Go to the documentation of io 0.3.0 Download io 0.3.0 archive
0.2.0 Aug 15, 2017 Go to the documentation of io 0.2.0 Download io 0.2.0 archive
0.1.0-git Jan 31, 2014 Go to the documentation of io 0.1.0-git Download io 0.1.0-git archive


This feature is new.
We welcome feedback.
More details: scoring.

We analyzed this package, and provided a score, details, and suggestions below.

  • completed on Jan 17, 2018
  • Dart: 2.0.0-dev.15.0
  • pana: 0.9.1


Describes how popular the package is relative to other packages. [more]
90 / 100
Code health derived from static analysis. [more]
100 / 100
Reflects how tidy and up-to-date the package is. [more]
100 / 100
Overall score:
Weighted score of the above. [more]


Detected platforms: Flutter, server

Multiple platform identified in libraries.


  • The description is too short.

    Add more detail about the package, what it does and what is its target use case. Try to write at least 60 characters.

  • Package is pre-v1 release.

    While there is nothing inherently wrong with versions of 0.*.*, it usually means that the author is still experimenting with the general direction API.

  • Maintain an example.

    None of the files in your example/ directory matches a known example patterns. Common file name patterns include: main.dart, example.dart or you could also use io.dart.


Package Constraint Resolved Available
Direct dependencies
Dart SDK >=1.22.0 <2.0.0
charcode ^1.0.0 1.1.1
meta ^1.0.2 1.1.2
path ^1.5.1 1.5.1
string_scanner >=0.1.5 <2.0.0 1.0.2
Transitive dependencies
source_span 1.4.0
Dev dependencies
dart_style ^1.0.7
test ^0.12.0
test_descriptor ^1.0.0