node.js fs模块学习

/**
 * Created by jjcheng on 2017/7/18.
 */
/*//输出到终端
process.stdout.write("Hello World!" + "\n");
//经过参数读取
process.argv.forEach(function(val, index, array){
   console.log(index + ": " + val);
});
//获取执行路径
console.log(process.execPath);
//平台信息
console.log(process.platform);
//输出当前目录
console.log("当前目录：" + process.cwd());
//输出当前版本
console.log("当前版本：" + process.version);
//输出内存使用状况
console.log(process.memoryUsage());*/
/*

var util = require("util");
function Base(){
   this.name = "base";
   this.base = 1991;
   this.sayHello = function(){
      console.log("Hello " + this.name);
   }
}

Base.prototype.showName = function(){
   console.log(this.name);
};

function Sub(){
   this.name = "sub";
}

util.inherits(Sub, Base);
var objBase = new Base();
objBase.showName();
objBase.sayHello();
console.log(objBase);

var objSub = new Sub();
objSub.showName();
//objSub.sayHello();
console.log(objSub);
*/
/*


var util = require("util");
function Person(){
   this.name = "byvoid";
   this.toString = function(){
      return this.name;
   };
}
var obj = new Person();
console.log(util.inspect(obj));
console.log(util.inspect(obj, true));

console.log("util.isArray([])="+util.isArray([]));
console.log(util.isArray(new Array));
console.log(util.isArray({}));

console.log(util.isRegExp(/some regexp/));
console.log(util.isRegExp(new RegExp("another regexp")));
console.log(util.isRegExp({}));

console.log(util.isDate(new Date()));
console.log(util.isDate(Date()));//false (without "new" returns a Sring
console.log(util.isDate({}));

console.log(util.isError(new Error()));
console.log(util.isError(new TypeError()));
console.log(util.isError({name:"Error", message:"an error occurred"}));

*/
/*

var filePath = "D:\\WebstormProjects\\node1\\input.txt";
var fs = require("fs");
//异步读取
fs.readFile(filePath, function(err, data){
   if(err){
      return console.error(err);
   }
   console.log("异步读取：" + data.toString());
});

//同步读取
var data = fs.readFileSync(filePath);
console.log("同步读取：" + data.toString());
console.log("程序执行完毕。");

*/
/*
var filePath = "D:\\WebstormProjects\\node1\\input.txt";
var fs = require("fs");
//异步打开文件
console.log("准备打开文件！");
fs.open(filePath, "r+", function(err, fd){
   if(err){
      return console.error(err);
   }
   console.log("文件打开成功！");
});

*/

/*

var filePath = "D:\\WebstormProjects\\node1\\input.txt";
var fs = require("fs");
fs.stat(filePath, function(err, stats){
   console.log(stats.isFile());
});
*/
/*

var filePath = "D:\\WebstormProjects\\node1\\input.txt";
var fs = require("fs");
console.log("准备打开文件!");
fs.stat(filePath, function(err, stats){
   if(err){
      return console.error(err);
   }
   console.log(stats);
   console.log("读取文件信息成功！");
   //检测文件类型
    console.log("是否为文件（isFile）?" + stats.isFile());
    console.log("是否为目录(isDirectory)?" + stats.isDirectory());
});
*/
/*

var filePath = "D:\\WebstormProjects\\node1\\input.txt";
var fs = require("fs");

console.log("准备写入文件");
fs.writeFile(filePath, "我是经过写入的文件内容！", function(err){
   if(err){
      return console.error(err);
   }
   console.log("数据写入成功！");
   console.log("------我是分割线------");
   console.log("读取写入的数据");
   fs.readFile(filePath, function(err, data){
      if(err){
         return console.error(err);
      }
      console.log("异步读取文件数据：" + data.toString());
   });
});

*/
/*

var filePath = "D:\\WebstormProjects\\node1\\input.txt";
var fs = require("fs");

var buf = new Buffer(1024);
console.log("准备打开已存在的文件！");
fs.open(filePath, "r+", function(err, fd){
   if(err){
      return console.error(err);
   }
   console.log("文件打开成功！");
   console.log("准备读取文件爱你：");
   fs.read(fd, buf, 0, buf.length, 0, function(err, bytes){
      if(err){
         console.log(err);
      }
      console.log(bytes + " 字节被读取");
      //仅输出读取的字节
       if(bytes > 0){
          console.log(buf.slice(0, bytes).toString());
       }
   });
});*/
/*

var filePath = "D:\\WebstormProjects\\node1\\input.txt";
var fs = require("fs");
var buf = new Buffer(1024);
console.log("准备打开文件！");
fs.open(filePath, "r+", function(err, fd){
   if(err){
      return console.error(err);
   }
   console.log("文件打开成功！");
   console.log("准备读取文件！");
   fs.read(fd, buf, 0, buf.length, 0, function(err, bytes){
      if(err){
         console.log(err);
      }
      //仅输出读取的字节
       if(bytes > 0){
         console.log(buf.slice(0, bytes).toString());
       }
       //关闭文件
       fs.close(fd, function(err){
          if(err){
             console.log(err);
          }
          console.log("文件关闭成功");
       });
   });
});
*/
/*

var filePath = "D:\\WebstormProjects\\node1\\input.txt";
var fs = require("fs");
var buf = new Buffer(1024);

console.log("准备打开文件");
fs.open(filePath, "r+", function(err, fd){
   if(err){
      return console.error(err);
   }
   console.log("文件打开成功！");
   console.log("截取10字节后的文件内容。");

   //截取文件
    fs.ftruncate(fd, 10, function(err){
       if(err){
          console.log(err);
       }
       console.log("文件截取成功。");
       console.log("读取相同的文件");
       fs.read(fd, buf, 0, buf.length, 0, function(err, bytes){
         if(err){
            console.log(err);
         }
         //仅输出读取的字节
         if(bytes > 0){
            console.log(buf.slice(0, bytes).toString());
         }
         //关闭文件
         fs.close(fd, function(err){
            if(err){
               console.log(err);
            }
            console.log("文件关闭成功！");
           });
       });
    });
});

*/
/*

var filePath = "D:\\WebstormProjects\\node1\\input.txt";
var fs = require("fs");
console.log("准备删除文件");
fs.unlink(filePath, function(err){
   if(err){
      return console.error(err);
   }
   console.log("文件删除成功！");
});
*/
/*
var filePath = "D:\\WebstormProjects\\node1\\input.txt";
var fs = require("fs");

console.log("建立目录");
fs.mkdir(filePath, function(err){
   if(err){
      return console.error(err);
   }
   console.log("目录建立成功。");
});*/
/*

var filePath = "D:\\WebstormProjects\\node1\\input.txt";
var fs = require("fs");
console.log("查看目录");
fs.readdir(filePath, function(err, files){
   if(err){
      return console.error(err);
   }
   files.forEach(function(file){
      console.log(file);
   });
});
*/
/*

var filePath = "D:\\WebstormProjects\\node1\\input.txt";
var fs = require("fs");
console.log("准备删除目录");
fs.rmdir(filePath, function(err, files){
   if(err){
      return console.error(err);
   }
   console.log("读取目录");
   fs.readdir(filePath, function(err, files){
      if(err){
         return console.error(err);
      }
      files.forEach(function(file){
         console.log(file);
      });
   });
});
*/