从命令行运行 Node.js 脚本
¥Run Node.js scripts from the command line
运行 Node.js 程序的通常方法是运行全局可用的 node 命令（安装 Node.js 后）并传递要执行的文件的名称。
¥The usual way to run a Node.js program is to run the globally available node command (once you install Node.js) and pass the name of the file you want to execute.
如果你的主 Node.js 应用文件是 app.js，你可以通过键入以下内容来调用它：
¥If your main Node.js application file is app.js, you can call it by typing:
node app.js
上面，你明确告诉 shell 使用 node 运行你的脚本。你也可以使用 "shebang" 行将此信息嵌入到你的 JavaScript 文件中。"shebang" 是文件中的第一行，它告诉操作系统使用哪个解释器来运行脚本。以下是 JavaScript 的第一行：
¥Above, you are explicitly telling the shell to run your script with node. You can also embed this information into your JavaScript file with a "shebang" line. The "shebang" is the first line in the file, and tells the OS which interpreter to use for running the script. Below is the first line of JavaScript:
#!/usr/bin/node
上面，我们明确给出了解释器的绝对路径。并非所有操作系统的 bin 文件夹中都有 node，但所有操作系统都应该有 env。你可以告诉操作系统以 node 作为参数运行 env：
¥Above, we are explicitly giving the absolute path of interpreter. Not all operating systems have node in the bin folder, but all should have env. You can tell the OS to run env with node as parameter:
#!/usr/bin/env node
// your javascript code
要使用 shebang，你的文件应该具有可执行权限。你可以通过运行为 app.js 授予可执行权限：
¥To use a shebang, your file should have executable permission. You can give app.js the executable permission by running:
chmod u+x app.js
在运行命令时，请确保你位于包含 app.js 文件的同一目录中。
¥While running the command, make sure you are in the same directory which contains the app.js file.
将字符串作为参数传递给 node，而不是文件路径
¥Pass string as argument to node instead of file path
要将字符串作为参数执行，你可以使用 -e、--eval "script"。将以下参数评估为 JavaScript。REPL 中预定义的模块也可以在脚本中使用。
¥To execute a string as argument you can use -e, --eval "script". Evaluate the following argument as JavaScript. The modules which are predefined in the REPL can also be used in script.
在 Windows 上，使用 cmd.exe 单引号将无法正常工作，因为它仅识别双 " 进行引用。在 Powershell 或 Git bash 中，' 和 " 均可使用。
¥On Windows, using cmd.exe a single quote will not work correctly because it only recognizes double " for quoting. In Powershell or Git bash, both ' and " are usable.
node -e "console.log(123)"
自动重新启动应用
¥Restart the application automatically
从 nodejs V16 开始，有一个内置选项可以在文件更改时自动重新启动应用。这对于开发目的很有用。要使用此功能，你需要将 `--watch' 标志传递给 nodejs。
¥As of nodejs V16, there is a built-in option to automatically restart the application when a file changes. This is useful for development purposes. To use this feature, you need to pass the `--watch' flag to nodejs.
node --watch app.js
因此，当你更改文件时，应用将自动重新启动。阅读 --watch 标志文档。
¥So when you change the file, the application will restart automatically.
Read the --watch flag documentation.