[feature] add shell option

execspawn.js

@@ -7,7 +7,7 @@ module.exports = function execstream(command, options) {
  options = extend({}, options);

  if (process.platform === 'win32') {
    file = 'cmd.exe';
    file = process.env.comspec || 'cmd.exe';
    args = ['/s', '/c', '"' + command + '"'];
    options.windowsVerbatimArguments = true;
  } else {
@@ -16,5 +16,9 @@ module.exports = function execstream(command, options) {
    options.windowsVerbatimArguments = false;
  }

  if (options && options.shell) {
    file = options.shell;
  }

  return spawn(file, args, options);
};

test.js

@@ -3,10 +3,18 @@ var test = require('tap').test;
var execstream = require('./execspawn.js');
var endpoint = require('endpoint');

test('simple test', function (t) {
test('default', function (t) {
  execstream('echo "hallo world";').stdout.pipe(endpoint(function (err, out) {
    t.equal(err, null);
    t.equal(out.toString(), 'hallo world\n');
    t.end();
  }));
});

test('shell option', function (t) {
  execstream('hallo world', { shell: 'echo' }).stdout.pipe(endpoint(function (err, out) {
    t.equal(err, null);
    t.equal(out.toString(), '-c hallo world\n');
    t.end();
  }));
});