Decompile python2.5-pyc

Gabriel Genellina gagsl-py2 at
Tue Sep 16 00:56:51 EDT 2008

En Mon, 15 Sep 2008 20:57:24 -0300, Manuel Ebert <maebert at> escribió:

> short story I accidentally wrote rm *.py into my makefile (yes, I am  
> old-fashioned, and yes, that was very, veeeery stupid) and - bad things  
> never come alone - my remote backup files are corrupted. To cut a sad  
> story short: I just kind of lost four months work on my bachelor's  
> thesis, well almost. I still have the pyc files (and backuped them on  
> virtually every device I have access to now), but despite intense  
> googling I couldn't find any free way of decompiling 2.5-code -- there  
> is and the online version of decompyle, but they charge  
> money (which I currently don't have), and the free version of decompyle  
> can't handle marshal data > 2.3, and I lack the skills necessary to  
> extend it to 2.5.
> Does anybody know something I don't, some home-brewn decompiler,  
> anything? I *am* quite desperate...

If your code doesn't use too much features post-2.3, you could try  
regenerating the .pyc files using the old marshal format and feed the  
resulting .pyc to decompyle - if you're lucky it may accept it...

--- begin ---
import marshal

MAGIC23 = ';\xf2\r\n'

def load_pyc(filename):
     f = open(filename, 'rb')
       magic =
       timestamp =
       codeobject = marshal.load(f)
     return magic, timestamp, codeobject

def dump_pyc_23(filename, timestamp, codeobject):
     assert len(timestamp)==4
     f = open(filename, 'wb')
       marshal.dump(codeobject, f, 0)

magic, timestamp, codeobject = load_pyc("test25.pyc")
dump_pyc_23("test23.pyc", timestamp, codeobject)
--- end ---

Good luck!

Gabriel Genellina

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