find and replace string in binary file

[loial]

Thanks Emile.

Unfortunately I have to use python 2.6 for this


On Wednesday, 5 March 2014 00:13:00 UTC, emile  wrote:
> On 03/04/2014 02:44 PM, Chris Angelico wrote:
> 
> > On Wed, Mar 5, 2014 at 12:18 AM, Peter Otten <__peter__ at web.de> wrote:
> 
> >> loial wrote:
> 
> >>
> 
> >>> How do I read a binary file, find/identify a character string and replace
> 
> >>> it with another character string and write out to another file?
> 
> >>>
> 
> >>> Its the finding of the string in a binary file that I am not clear on.
> 
> >>
> 
> >> That's not possible. You have to convert either binary to string or string
> 
> >> to binary before you can replace. Whatever you choose, you have to know the
> 
> >> encoding of the file.
> 
> >
> 
> > If it's actually a binary file (as in, an executable, or an image, or
> 
> > something), then the *file* won't have an encoding, so you'll need to
> 
> > know the encoding of the particular string you want and encode your
> 
> > string to bytes.
> 
> 
> 
> 
> 
> On 2.7 it's as easy as it sounds without having to think much about 
> 
> encodings and such.  I find it mostly just works.
> 
> 
> 
> emile at paj39:~$ which python
> 
> /usr/bin/python
> 
> emile at paj39:~$ python
> 
> Python 2.7.3 (default, Sep 26 2013, 16:38:10)
> 
> [GCC 4.7.2] on linux2
> 
> Type "help", "copyright", "credits" or "license" for more information.
> 
>  >>> image = open('/usr/bin/python','rb').read()
> 
>  >>> image.find("""Type "help", "copyright", "credits" """)
> 
> 1491592
> 
>  >>> image = image[:1491592]+"Echo"+image[1491592+4:]
> 
>  >>> open('/home/emile/pyecho','wb').write(image)
> 
>  >>>
> 
> emile at paj39:~$ chmod a+x /home/emile/pyecho
> 
> emile at paj39:~$ /home/emile/pyecho
> 
> Python 2.7.3 (default, Sep 26 2013, 16:38:10)
> 
> [GCC 4.7.2] on linux2
> 
> Echo "help", "copyright", "credits" or "license" for more information.
> 
> 
> 
> YMMV,
> 
> 
> 
> Emile