editing a binary file

[Rolf Nielsen]

Anton Shterenlikht wrote:
> On Fri, Dec 18, 2009 at 02:09:58AM +0100, Rolf Nielsen wrote:
>> Anton Shterenlikht wrote:
>>> I'm creating binary files in fortran.
>>> Fortran adds 4 byte record delimiters at the beginning
>>> and the end of each record, which, in the case of a binary
>>> file, is just at the beginning and at the end of the file.
>>> I need to delete these record delimiters, because the
>>> software I use to visualise the binary files interprets
>>> them as data. But I don't know how. I've looked at
>>> hexdump and od, but those are only dumping (I think)
>>> file contents, and I cannot see how to edit a file with them.
>>>
>>> Any advice?
>>>
>>> many thanks
>>> anton
>>>
>> Hello Anton,
>>
>> My bet would be /usr/ports/editors/hexedit. Been a while since I've used 
>> it, but AFAIR, it has a curses or a curses like interface, and it's 
>> fairly simple to use, yet sufficiently powerful for most normal binary 
>> editing. If you want a GUI, I believe gnome (and probably KDE as well) 
>> has its own hex editor.
> 
> thank you. hexedit does the job on small files, but is quite
> clunky. If I've a xGB file and I need to delete the first and
> the last record, this becomes quite hard, if at all possible.
> 
> I didn't appreciate it's not that simple.
> 
> Perhaps I can read a file with C and write back? I can't
> remember if C supports binary files, and whether it
> also writes some record delimiters.
> 
> many thanks
> anton
> 

How about one of these then?


http://www.freebsd.org/cgi/url.cgi?ports/editors/bless/pkg-descr
Main Features
-------------
   * Efficient editing of large data files.
   * Multilevel undo - redo operations.
   * Customizable data views.
   * Fast data rendering on screen.

http://www.freebsd.org/cgi/url.cgi?ports/editors/lfhex/pkg-descr
Features:
    - Low memory usage with respect to filesize. Opening a 2gig file 
requires
      only ~1.4megs of additional memory.
    - Fast load times.
    - Fast save times.
    - Infinite undo/redo.
    - Conversion dialog
    - Search function.
    - Shows modified regions in alternate color.
    - Scalable working area. Resize can use as much screen as you give it.
    - Multiple editing modes (can switch on the fly)
    - Runtime configurable bytes per column.
    - binary comparison user interface

I haven't tried either of them myself, but they do look promising.

Rolf