Fsutil is a command-line utility that you can use to perform many FAT and NTFS file system related tasks, such as managing reparse points, managing sparse files, dismounting a volume, or extending a volume. Because fsutil is quite powerful, it should only be used by advanced users who have a thorough knowledge of Windows XP. In addition, you must be logged on as an administrator or a member of the Administrators group in order to use fsutil.
The following table lists the fsutil subcommands.
Queries, changes, enables, or disables the settings for generating 8.3 character-length file names, accepting extended characters in 8.3 character-length file names on NTFS volumes, updating the last access timestamp on NTFS volumes, how often quota events are written to the system log, and the amount of disk space reserved of the MFT Zone.
Queries whether volume's dirty bit is set. Sets a volume's dirty bit. When a volume's dirty bit is set, autochk automatically checks the volume for errors the next time the computer is restarted.
Typically used by support professionals. Finds a file by its security identifier, queries allocated ranges for a file, sets a file's short name, sets a file's valid data length, or sets zero data for a file.
Typically used by support professionals. Lists all drives, queries the drive type, queries volume information, queries NTFS-specific volume information, or queries file system statistics.
Creates a hard link. A hard link is a directory entry for a file. Every file can be considered to have at least one hard link. On NTFS volumes, each file can have multiple hard links, and thus a single file can appear in many directories (or even in the same directory with different names). Because all of the links reference the same file, programs can open any of the links and modify the file. A file is deleted from the file system only after all links to it have been deleted. After you create a hard link, programs can use it like any other file name.
Typically used by support professionals. Manages object identifiers, which are used by Windows XP to track objects such as files and directories.
Manages disk quotas on NTFS volumes in order to provide more precise control of network-based storage. Disk quotas are implemented on a per-volume basis and enable both hard- and soft-storage limits to be implemented on a per-user basis.
Typically used by support professionals. Queries or deletes reparse points, which are NTFS file system objects that have a definable attribute containing user-controlled data, and are used to extend functionality in the input/output (I/O) subsystem. Reparse points are used for directory junction points and volume mount points. They are also used by file system filter drivers to mark certain files as special to that driver.
Manages sparse files A sparse file is a file with one or more regions of unallocated data in it. A program will see these unallocated regions as containing bytes with the value zero, but there is actually no disk space used to represent these zeros. In other words, all meaningful or nonzero data is allocated, whereas all non-meaningful data (large strings of data composed of zeros) is not allocated. When a sparse file is read, allocated data is returned as stored and unallocated data is returned, by default, as zeros, in accordance with the C2 security requirement specification. Sparse file support allows data to be deallocated from anywhere in the file.
Typically used by support professionals. Manages the update sequence number (USN) change journal, which provides a persistent log of all changes made to files on the volume.
Manages a volume. Dismounts a volume or queries to see how much free space is available on a disk.
To view help for the available subcommands at the command prompt, type fsutil, type the subcommand, and then type help (that is, fsutil subcommand help).
Command-line reference A-Z