var fileManager = NSFileManager()

        // 取得文件夹的路径，注意：末尾加/与不加同样，推荐末尾加/
        // Define folderPath
        var filePath = "/Users/Star/desktop/PathName/"


        // 获得文件夹下文件名称集合。注：此处获得文件名称，而不是全部路径
        // Get all filenames array in the folder, warning: only filename and not full path
        var oldFileNamesArray = fileManager.contentsOfDirectoryAtPath(filePath, error: nil) as [String]
        
        for oldFileName in oldFileNamesArray{

            // 取得旧名称的全部路径
            // Append to file full name
            var oldFilePathName = filePath + oldFileName

            // 取得需要修改的字的所在范围
            // Get range of replace string
            var rangeString = oldFileName.rangeOfString("OldName", options: NSStringCompareOptions.LiteralSearch, range: nil, locale: nil);
            if rangeString == nil {
                continue
            }

            // Swift中的String 是引用类型
            // 不能直接修改 for in 遍历的元素
            // Define a new string Becauce we cannot direct replacing the for in circulation element
            var newFileName = oldFileName

            // 替换掉Old字符串
            // replaced to NewName
            newFileName.replaceRange(rangeString!, with: "NewName")
            
            // 取得新名词的全部路径
            // Get the new full path
            var newFilePathName = filePath + newFileName
            
            // 执行文件移动函数,此函数能实现文件名称修改
            // Execute the function "moveItemAtPath" with moving the file
            // The function can replace "rename"
            // return execution result
            if fileManager.moveItemAtPath(oldFilePathName, toPath: newFilePathName, error: nil){
                println("成功 successful")
            }
            else{
                println("失败 failed")
            }
            
        }