text: var parse = require('shell-quote').parse;
  var exec = require('child_process').exec;
  var path = require('path');
  var echo = process.execPath + ' ' + path.join(__dirname, 'bin/echo');
  var fs = require('fs');
  
  module.exports = function (str, opts) {
      var parts = parse(str);
      for (var i = 0; i < parts.length; i++) {
          if (parts[i].op) break;
      }
      if (i === parts.length) { // no ops
          var w = fs.createWriteStream(str);
          w.once('finish', function () { w.emit('exit', 0) });
          w.once('error', function (err) { w.emit('exit', 1) });
          return w;
      }
      else {
          if (parts[parts.length-1].op === '|') {
              str += echo;
          }
          if (parts[0].op === '|') {
              str = echo + str;
          }
          if (parts[0].op === '>') {
              str = echo + str;
          }
      }
      var p = exec(str, opts);
      p.stderr.pipe(process.stderr, { end: false });
      p.stdout.pipe(process.stdout, { end: false });
      p.once('exit', function (code) { p.stdin.emit('exit', code) });
      return p.stdin;
  };
  