main.dart

import 'dart:async';
import 'dart:convert';
import 'dart:io';

void main() async {
  
 var ls = await start('ls');
  var head = await start('head');
  var headStdout = head.stdout;

  ls.stdout
      .transform(utf8.decoder)
      .transform(const LineSplitter())
      .map((line) {
        print(line);
        return '1: line';
      })
      .transform(utf8.encoder)
      .listen((line) => head.stdin.add(line), onDone: () {
      });

  headStdout
      .transform(utf8.decoder)
      .transform(const LineSplitter())
      .listen((line) => print(line), onDone: () {
    head.stdin.close();
  });
}

Future<Process> start(String command) async
{
  
    var process =  Process.start(
      command,
      [],
    );
  return process;
}