Editing Hex editor (section)

==Details==
[[File:Hexedit-screenshot.png|thumb|right|253px|Screenshot of a common hex editor (hexedit by Pascal Rigaux (Pixel))]]
With a hex editor, a user can see or edit the raw and exact contents of a file, as opposed to the interpretation of the same content that other, higher level [[application software]] may associate with the [[file format]]. For example, this could be raw image data, in contrast to the way image editing software would interpret and show the same file.

Hex editors may be used to correct [[Data corruption|data corrupted]] by system or application program problems where it may not be worthwhile to write a special program to make the corrections.  They are useful to bypass application edit checks which may prevent correction of erroneous data. They have been used to "patch" executable programs to change or add a few instructions as an alternative to recompilation.  Program fixes for [[IBM mainframe]] systems are sometimes distributed as patches rather than distributing a complete copy of the affected program.

In most hex editor applications, the [[data]] of the computer file is represented as [[hexadecimal]] values grouped in 4 groups of 4 [[byte]]s (or two groups of 8 bytes), followed by one group of 16 printable [[ASCII]] characters which correspond to each pair of hex values (each byte). Non-printable ASCII characters (e.g., Bell) and characters that would take more than one character space (e.g., tab) are typically represented by a dot (".") in the following ASCII field.

; Size limits
Unlike conventional text editors, Hex editors are able to efficiently handle files with indefinite sizes, as only a portion of the file is loaded while browsing it and modified when saving it, rather than the entire file at once.