stripping the first byte from a binary file

[Stefan Behnel]

rvr wrote:
> On Jul 11, 1:28 pm, Steven D'Aprano
> <ste... at REMOVE.THIS.cybersource.com.au> wrote:
>> On Wed, 11 Jul 2007 01:06:04 +0000, rvr wrote:
>>> Is there a way to edit the file in place? The best I seem to be able to
>>> do is to use your second solution to read the file into the string, then
>>> re-open the file for writing and put the whole thing back (minus the
>>> first byte). Thanks.
>> I don't believe that any of the popular operating systems in common use
>> (Windows, Linux, Mac, *BSD) have any such functionality.
>>
>> For safety, you are best off copying the file (minus the first byte) to a
>> temporary file, then renaming the copy over the original. That way if
>> your process dies midway through copying the file, you don't lose data.
>>
>> Renaming the file is atomic under Linux and (probably) Mac, so it is as
>> safe as possible. Even under Windows, which isn't atomic, it has a
>> smaller margin for disaster than over-writing the file in place.
> 
> Thanks for your response. While searching for solution, I found this:
> 
>    http://mail.python.org/pipermail/python-list/2001-December/116519.html
> 
> Quoting from it:
> 
> """
> Replace 2 bytes in place beginning at offset 100 (101st byte):
> 
>     f = open('text_input', 'r+b')
>     f.seek(100)
>     f.write(chr(123) + chr(0x80))
>     f.seek(0,2)
>     f.close()
> """
> 
> Can I use the seek() and write() methods in a similar way to remove
> the first byte? For whatever reason I can't seem to make it work
> myself. Thanks again.

Funny. I just happened to read ESR's "how to ask questions the smart way" and
your posts match quite a few of the examples. :)

No, you can't. Steven's solution is what I'd go for.

Stefan