用Windows自带命令行彻底删除文件

在windows 2000以上版本都内置了一个这样的工具——cipher.exe。cipher使用方法很简单，在命令行窗口中，键入： cipher /w:盘符:/目录
其中，目录是可选的，用于卷挂接点。一般情况下，只写磁盘盘符就行了。比如清除e盘，就用“cipher /w:e”。
命令开始运行后，会依次用0x00、 0xff和随意数字覆盖该分区中的全部空闲空间，能够消除任何已删除文件的痕迹。 此命令适用于ntfs格式的磁盘。cipher命令存在于windows 2000、windows xp、windows 2003和vista。

How To Use Cipher.exe to Overwrite Deleted Data in Windows

How to Use the Cipher Security Tool to Overwrite Deleted Data

To overwrite deleted data on a volume by using Cipher.exe, use the /w switch with the cipher command. Use the following steps:

1. Quit all programs.
2. Click Start, click Run, type cmd, and then press ENTER.
3. Type cipher /w:driveletter:\foldername, and then press ENTER. Specify the drive and the folder that identifies the volume that contains the deleted data that you want to overwrite. Data that is not allocated to files or folders will be overwritten. This permanently removes the data. This can take a long time if you are overwriting a large space.
   
   Note With mount points in Windows 2000, you can mount a volume on any empty folder on an NTFS volume. When you do this, the mounted volume does not have a drive letter of its own. The only way to address that volume is by using the path where you created the mount point. Therefore, the /w switch requests a path of a folder, and from that, it determines the associated volume to wipe. Because of the way the file system works, the whole volume must be wiped. A file can be written anywhere on the volume at any time. A folder does not address a specific physical location on disk but is a logical container for file entries in the volume's table of contents (MFT or FAT). To make sure that there is no leftover data in unallocated space, all unallocated space on the volume must be wiped.