How do I get the directory of the current script, in Dart?

If you're doing this for a console based app (e.g. in a unit test) and intend to use the output to open a file for reading or writing, it's more helpful to use Platform.script.path:

import "package:path/path.dart" show dirname, join;
import 'dart:io' show Platform;

main() {
  print(join(dirname(Platform.script.path), 'test_data_file.dat'));
}

The result of that command can be used with a File object and be opened/read (e.g. if you have a unit test that needs to read/compare sample data, or a console program that needs to open a file relative to the current script for some other reason).

The easiest way to find the script's directory is to use the path package.

import "package:path/path.dart" show dirname;
import 'dart:io' show Platform;

main() {
  print(dirname(Platform.script.toString()));
}

Put the path package into your pubspec.yaml:

dependencies:
  path: any

And be sure to run pub get to download and link the path package.

Using Platform.script.path doesn't work in all circumstances.

If your script is compiled or running as a unit test you won't get the expected results.

This is from the dcli project (https://pub.dev/packages/dcli)

If you are using dcli you can call:

// absolute path including the script name
DartScript.self.pathToScript;

or

// just the absolute path to the script's directory
DartScript.self.pathToScriptDirectory;

This code works if the script is run via dart <scriptname.dart>, if you compile the script or if you script is a unit test.

Here is the internal implementation.

static String get _pathToCurrentScript {
    if (_current == null) {
      final script = Platform.script;

      String _pathToScript;
      if (script.isScheme('file')) {
        _pathToScript = Platform.script.toFilePath();

        if (_isCompiled) {
          _pathToScript = Platform.resolvedExecutable;
        }
      } else {
        /// when running in a unit test we can end up with a 'data' scheme
        if (script.isScheme('data')) {
          final start = script.path.indexOf('file:');
          final end = script.path.lastIndexOf('.dart');
          final fileUri = script.path.substring(start, end + 5);

          /// now parse the remaining uri to a path.
          _pathToScript = Uri.parse(fileUri).toFilePath();
        }
      }

      return _pathToScript;
    } else {
      return _current.pathToScript;
    }
  }

  static bool get _isCompiled =>
      basename(Platform.resolvedExecutable) ==
      basename(Platform.script.path);