nodejs中__filename和__dirname的區別

　　在Node-API里面對二者的解釋是：

__filename 

 

The filename of the code being executed. This is the resolved absolute path of this code file. For a main program this is not necessarily the same filename used in the command line. The value inside a module is the path to that module file.

Example: running node example.js from /Users/mjr

console.log(__filename);
// /Users/mjr/example.js

__filename isn't actually a global but rather local to each module.

 

__dirname 

 

The name of the directory that the currently executing script resides in.

Example: running node example.js from /Users/mjr

console.log(__dirname);
// /Users/mjr

__dirname isn't actually a global but rather local to each module.

　　這大概的意思就是，__filename指的是當前解析文件的實際物理地址，而__dirname指的是此文件在被執行時所在的地址

 

　 　具體的可以通過下面兩個代碼來看

　　test.js

var text = require("./test2");
console.log("the test.js's filename is: %s",__filename);
console.log("the test.js's dirname is %s",__dirname);
text.start();

　　test2.js

function start(){
    console.log("the test2.js's filename is: %s",__filename);
    console.log("the test2.js's dirname is %s",__dirname);
}
exports.start = start;

在這里，test.js  require了 test2.js，二者是在同一個目錄下面

然后我們執行node test.js

結果是：

the test.js's filename is: /home/xing/ANodeJsWebSite/node/test.js
the test.js's dirname is /home/xing/ANodeJsWebSite/node
the test2.js's filename is: /home/xing/ANodeJsWebSite/node/test2.js
the test2.js's dirname is /home/xing/ANodeJsWebSite/node

然后我們把test2.js移到上層目錄，更改一下test.js里面的require地址，再運行test.js

the test.js's filename is: /home/xing/ANodeJsWebSite/node/test.js
the test.js's dirname is /home/xing/ANodeJsWebSite/node
the test2.js's filename is: /home/xing/ANodeJsWebSite/test2.js
the test2.js's dirname is /home/xing/ANodeJsWebSite

可見__filename始終是用絕對路徑顯示一個文件的位置，而__dirname則是該文件所在目錄的絕對路徑