About: jhead is an Exif Jpeg header and thumbnail manipulation tool.
  Fossies Dox: jhead-  ("unofficial" and yet experimental doxygen-generated source code documentation)  

jhead Documentation

Some Fossies usage hints in advance:

  1. To see the Doxygen generated documentation please click on one of the items in the steelblue colored "quick index" bar above or use the side panel at the left which displays a hierarchical tree-like index structure and is adjustable in width.
  2. If you want to search for something by keyword rather than browse for it you can use the client side search facility (using Javascript and DHTML) that provides live searching, i.e. the search results are presented and adapted as you type in the Search input field at the top right.
  3. Doxygen doesn't incorporate all member files but just a definable subset (basically the main project source code files that are written in a supported language). So to search and browse all member files you may visit the Fossies jhead- contents page and use the Fossies standard member browsing features (also with source code highlighting and additionally with optional code folding).
JHEAD is a simple command line tool for displaying and some manipulation
of EXIF header data embedded in Jpeg images from digital cameras.

For command line options, please see usage.html

There is also a suite of regression tests in the "tests" directory.
After compiling, from the tests directory run "runtests"
To check the results, do "diff expected-txt results-txt"

Some notes:

    When I first wrote Jhead back in 1999, there wasn't much software around
    for looking inside Exif headers, so I wrote jhead for that task.  Since 
    then, a lot of much more sophisticated programs for looking inside Exif 
    headers have been written, many with GUIs, and features that Jhead lacks.
    Seeing that Jhead does everything I need it to do, My goal is not to have 
    every feature imaginable.  Rather, I want Jhead to be a small, simple, 
    easy to understand program.  My goal is that if you need to understand 
    Exif internals, or add Exif capability to your program, Jhead is the 
    place to cut and paste code from.
    If jhead doesn't have a feature you want, look for "exiftool".  Exiftool
    has any feature you could imageine, but it's also 100x bigger and much
    If you find that it dies on a certain jpeg file, send it to me, and I 
    will look at it.



    Make sure visual C is on your path (I use version 6 from 1998, 
    but it shouldn't matter much).
    Run the batch file make.bat

    Linux & Unices:

    type 'make'.


    Although I have never done so myself, people tell me it compiles
    under platforms as diverse as such as Mac OS-X, or NetBSD on Mac68k.
    Jhead doesn't care about the endian-ness of your CPU, and should not
    have problems with processors that do not handle unaligned data,
    such as ARM. 

    Jhead has also made its way into various Linux distributions and ports
    trees, so you might already have it on your system without knowing.


    Jhead is public domain software - that is, you can do whatever you want
    with it, and include it software that is licensed under the GNU or the 
    BSD license, or whatever other licence you chose, including proprietary
    closed source licenses.  Although not part of the license, I do expect
    common courtesy, please.

    If you do integrate the code into some software of yours, I'd appreciate
    knowing about it though. 

Matthias Wandel