How to modify binary file in emacs/vi

How to modify binary file in emacs/vi

[Datta Patil]

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Hi all ,

I have binary file(it looks like 101010100100001001001)
I have opened in emac....in hex mode(by giving ESC X--->hexl mode)
now it looks like (1ad3 89f0 0ba2.....)

Now i want to change to :
1ad3 89f0 0ba2      original file
2bd3 89f0 0ba2      new file(say)
but when i type 2 ...it takes its asciii value & changes two bytes.What i
want is when i press 2 , its hexadecimal value(i.e. 2) insted of ascii value
should appear.

Is there any method to change one-nible value in emacs or vi .
Plz help ...its v imp & will save our lot of time.(Basically in above case
we r trying to corrupt data)
Note : input file is binary file.


Thanx lot in advance.

Regards/Mit freundlichen Grüßen,
Datta Patil

Re: How to modify binary file in emacs/vi

[Eli Zaretskii]

> From: "Datta Patil" <dattatraya.patil@in.bosch.com>
> Newsgroups: gnu.emacs.help
> Date: Fri, 27 Feb 2004 20:14:52 +0530
> 
> Now i want to change to :
> 1ad3 89f0 0ba2      original file
> 2bd3 89f0 0ba2      new file(say)
> but when i type 2 ...it takes its asciii value & changes two bytes.What i
> want is when i press 2 , its hexadecimal value(i.e. 2) insted of ascii value
> should appear.
> 
> Is there any method to change one-nible value in emacs or vi .

In the Hexl buffer, type "C-h m".  Emacs will pop up a window that
describes the various features of the Hexl mode, including several
methods of modifying bytes and nibbles of the original file.  "C-M-x"
seems to be the command that you are looking for, but perhaps
something else is more convenient, so I suggest to read the whole text
displayed by "C-h m".