var path = require('path');
console.log(path.dirname('/foo/bar/baz/asdf/a.txt')); // /foo/bar/baz/asdf
console.log(path.dirname('/foo/bar/baz/asdf/')); // /foo/bar/baz
console.log(path.dirname('C:/test/aaa')); // C:/test

var path = require('path');
console.log(path.basename('/foo/bar/baz/asdf/a.txt')); // a.txt
console.log(path.basename('/foo/bar/baz/asdf/a.txt','.txt')); // a
console.log(path.basename('/foo/bar/baz/asdf/')); // asdf
console.log(path.basename('C:/test/aaa')); // aaa

var path = require('path');
console.log(path.extname('/foo/bar/baz/asdf/a.txt')); // .txt
console.log(path.extname('/foo/bar/baz/asdf/a.txt.b')); // .b
console.log(path.extname('/foo/bar/baz/asdf/a.')); // .
console.log(path.extname('C:/test/aaa/.')); // ''
console.log(path.extname('C:/test/aaa')); // ''

var path = require('path');
console.log(path.sep); // win下为\，*nix下为/
console.log('foo\\bar\\baz'.split(path.sep)); // [ 'foo', 'bar', 'baz' ]
console.log('foo/bar/baz'.split(path.sep)); // win下返回['foo/bar/baz']，但在*nix系统下会返回['foo','bar','baz']

var path = require('path');
console.log(path.delimiter); //win下为“;”，*nix下为“:”
console.log(path.sep); // win下为\，*nix下为/

var path = require('path');
console.log(path.normalize('a/b/c/../user/bin'));//a\b\user\bin
console.log(path.normalize('a/b/c///../user/bin/'));//a\b\user\bin\
console.log(path.normalize('a/b/c/../../user/bin'));//a\user\bin
console.log(path.normalize('a/b/c/.././///../user/bin/..'));//a\user
console.log(path.normalize('a/b/c/../../user/bin/../../'));//a\
console.log(path.normalize('a/../../user/bin/../../'));//..\
console.log(path.normalize('a/../../user/bin/../../../../'));//..\..\..\
console.log(path.normalize('./a/.././user/bin/./'));//user\bin\

var path = require('path');
console.log(path.join('////./a', 'b////c', 'user/'));//\a\b\c\user
console.log(path.join('a', '../../', 'user/'));//..\user\

path.resolve('foo/bar', '/tmp/file/', '..', 'a/../subfile')

cd foo/bar
cd /tmp/file/
cd ..
cd a/../subfile
pwd

var path = require('path');
console.log(path.resolve('.', 'testFiles/..', 'trdLayer'));//D:\project\trdLayer
console.log(path.resolve('..', 'testFiles', 'a.txt'));//D:\testFiles\a.txt
console.log(path.resolve('D:', 'abc', 'D:/a'));//D:\a
console.log(path.resolve('abc', 'ok.gif'));//D:\project\abc\ok.gif
console.log(path.resolve('abc', '..', 'a/../subfile')); //D:\project\subfile

var path = require('path');
console.log(path.isAbsolute('../testFiles/secLayer'));//false
console.log(path.isAbsolute('./join.js'));//false
console.log(path.isAbsolute('temp'));//false
console.log(path.isAbsolute('/temp/../..'));//true
console.log(path.isAbsolute('E:/github/nodeAPI/abc/efg'));//true
console.log(path.isAbsolute('///temp123'));//true

path.resolve(from, path.relative(from, to)) == path.resolve(to)

var path = require('path');
console.log(path.relative('C:\\\test', 'C:\\\impl\\bbb'));//..\impl\bbb
console.log(path.relative('C:/test/aaa', 'C:/bbb'));//..\..\bbb
console.log(path.relative('C:/test/aaa', 'D:/bbb'));//D:\bbb