fsutil file [createnew] FileName Length

fsutil file [findbysid] UserName Directory

fsutil file [queryallocranges] offset=Offset length=Length FileName

fsutil file [setshortname] FileName ShortName

fsutil file [setvaliddata] FileName DataLength

fsutil file [setzerodata] offset=Offset length=Length FileName

createnew

Creates a file of the specified name and size, whose content consists of zeroes.

FileName

Specifies the full path to the file including the file name and extension, for example C:\documents\filename.txt.

Length

Specifies the file's valid data length.

findbysid

On NTFS volumes where Disk Quotas are enabled, finds files that belong to a specified user. The user is identified by their user name. Findbysid is very efficient since it scans through the NTFS master file table (MFT), which is much more efficient than a recursive search through the directory structure.

UserName

Specifies the user's user name or logon name.

Directory

Specifies the full path to the directory, for example C:\users.

queryallocranges

Queries the allocated ranges for a file on an NTFS volume. Useful for determining whether a file has sparse regions.

offset=Offset

Specifies the start of the range to set to zeroes.

length=Length

Specifies the length of the range, in bytes.

setshortname

Sets the short name (8.3 character-length file name) for a file on an NTFS volume.

ShortName

Specifies the file's shortname.

setvaliddata

Set the valid data length for a file on an NTFS volume.

DataLength

Specifies the length of the file in bytes.

setzerodata

Sets a range (specified by Offset and Length) of the file to zeroes, which empties the file. If the file is a sparse file, the underlying allocation units are decommitted.

• Using setvaliddata
  In NTFS, there are two important concepts of file length: the end-of-file (EOF) marker and the Valid Data Length (VDL). The EOF indicates the actual length of the file. The VDL identifies the length of valid data on disk. Any reads between VDL and EOF automatically return 0 in order to preserve the C2 object reuse requirement.
  The setvaliddata parameter is only available for administrators because it requires the Perform volume maintenance tasks (SeManageVolumePrivilege) privilege. This feature is only required for advanced multimedia and system area network scenarios. The setvaliddata parameter must be a positive value that is greater than the current VDL, but less than the current file size.
  Programs might find it useful to set a VDL when:
  
  • Writing raw clusters directly to disk through a hardware channel. This allows the program to inform the file system that this range contains valid data that can be returned to the user.
    
  • Creating large files where performance is an issue. This avoids the time it takes to fill the file with zeroes when the file is created or extended.
    

To find files owned by scottb on drive C, type:

fsutil file findbysid scottb C:\users

To query the allocated ranges for a file on an NTFS volume, type:

fsutil file queryallocranges offset=1024 length=64 C:\Temp\sample.txt

To set the short name for the file Longfilename.txt on drive C to Longfile.txt, type:

fsutil file setshortname C:\longfilename.txt longfile.txt

To set the valid data length for a file on an NTFS volume, type:

fsutil file setvaliddata C:\testfile.txt 4096

To set a range of a file on an NTFS volume to zeros and thus empty it, type:

fsutil file setzerodata offset=100 length=150 C:\Temp\sample.txt