Laravel PHP命令未找到

我一直在使用作曲家没有问题安装Laravel，但是当我尝试执行的 laravel 的在我的终端我有这样的典型错误：

I have installed Laravel using composer without problems, but when I try to execute "laravel" in my terminal I have this typical error:

-bash：laravel：找不到命令

-bash: laravel: command not found

如果读官方网站的文档，我需要做的是：

If a read the documentation of the official site I need to do that:

请确保放置在〜/ .composer /供应商/ bin目录在PATH所以laravel可执行文件运行时发现的 laravel 的在终端命令。

Make sure to place the ~/.composer/vendor/bin directory in your PATH so the laravel executable is found when you run the laravel command in your terminal.

但我不知道怎么做（我在终端控制台命令新）

But I don't know how to do (I'm new on terminal console commands).

您能帮我吗？谢谢！