Editing File system (section)

=== Utilities ===

Typically, a file system can be managed by the user via various utility programs.

Some utilities allow the user to create, configure and remove an instance of a file system. It may allow extending or truncating the space allocated to the file system.

{{Anchor|DENTRY}}
Directory utilities may be used to create, rename and delete ''directory entries'', which are also known as ''dentries'' (singular: ''dentry''),<ref>{{cite book
 | last1                 = Mohan
 | first1                = I. Chandra
 | title                 = Operating Systems
 | url                   = https://books.google.com/books?id=eei_jHVJi3oC
 | location              = Delhi
 | publisher             = PHI Learning Pvt. Ltd.
 | date      = 2013
 | page                  = 166
 | isbn                  = 9788120347267
 | access-date            = 2014-07-27
 | quote                 = The word dentry is short for 'directory entry'. A dentry is nothing but a specific component in the path from the root. They (directory name or file name) provide for accessing files or directories[.]
}}</ref> and to alter metadata associated with a directory. Directory utilities may also include capabilities to create additional links to a directory ([[hard link]]s in [[Unix]]), to rename parent links (".." in [[Unix-like]] operating systems),{{Clarify|date=July 2014}} and to create bidirectional links to files.

File utilities create, list, copy, move and delete files, and alter metadata. They may be able to truncate data, truncate or extend space allocation, append to, move, and modify files in-place. Depending on the underlying structure of the file system, they may provide a mechanism to prepend to or truncate from the beginning of a file, insert entries into the middle of a file, or delete entries from a file. Utilities to free space for deleted files, if the file system provides an undelete function, also belong to this category.

Some file systems defer operations such as reorganization of free space, secure erasing of free space, and rebuilding of hierarchical structures by providing utilities to perform these functions at times of minimal activity. An example is the file system [[defragmentation]] utilities.

Some of the most important features of file system utilities are supervisory activities which may involve bypassing ownership or direct access to the underlying device. These include high-performance backup and recovery, data replication, and reorganization of various data structures and allocation tables within the file system.