fs.readFile(‘c:\\tmp\\helloworld.txt‘,‘utf8‘,function(err,data){console.log(data);})
var token=fs.readFileSync(‘c:\\tmp\\toekn.txt‘,‘utf8‘);
fs.writeFile(‘c:\\tmp\\helloworld.txt‘, ‘Hello World! now, hello again!‘)
fs.exists(‘c:\\tmp\\helloworld.txt‘,function(exists){console.log(exists);})
fs.existsSync(‘c:\\tmp\\helloworld.txt‘)
http://nodejs.org/api/fs.html#fs_fs_exists_path_callback
https://docs.nodejitsu.com/articles/file-system/how-to-read-files-in-nodejs
原文：http://www.cnblogs.com/zyip/p/4146823.html