Add shell.execSync

src/shell.js

@@ -2,7 +2,8 @@
 
 exports = module.exports = {
     sudo: sudo,
-    exec: exec
+    exec: exec,
+    execSync: execSync
 };
 
 var assert = require('assert'),
@@ -13,6 +14,13 @@ var assert = require('assert'),
 
 var SUDO = '/usr/bin/sudo';
 
+function execSync(tag, cmd) {
+    assert.strictEqual(typeof tag, 'string');
+    assert.strictEqual(typeof cmd, 'string');
+
+    child_process.execSync(cmd, { stdio: 'inherit' });
+}
+
 function exec(tag, file, args, callback) {
     assert.strictEqual(typeof tag, 'string');
     assert.strictEqual(typeof file, 'string');