Decompiling python bytecode with pycdc

We somehow lost the correct working version of a python file for a project, but one of our servers still had the pyc file (which was working fine in production).  To fix this,  went hunting for a good solution to get back our sourcecode.

From what I found, it seems the pycdc library is the best option currently, though there is also:

• https://github.com/wibiti/uncompyle2
• http://unpyc.sourceforge.net/

When I tried unpyc it threw and error for me, and uncomplye2 only works with 2.7.

Here are the steps to setup pycdc.  These instructions are for Centos 5.3, so they may need to be tweaked for your system.

Install CMake

• I needed to do this because unpyc needs version 2.8+, but yum on Centos 5.3 installs 2.6.6 by default
• A full list of versions is here: http://www.cmake.org/cmake/resources/software.html

wget http://www.cmake.org/files/v2.8/cmake-2.8.12.2.tar.gz
tar xzvf cmake-2.8.12.2.tar.gz
cd cmake-2.8.10.2
./bootstrap
make
make install

Download and compile pycdc

git clone git@github.com:zrax/pycdc.git
cd pycdc
/usr/local/bin/cmake ../pycdc/
make

Using pycdc to decompile

The program outputs to stdout, so redirect to a file.

./pycdc/pycdc filename.pyc > filename.py

That's it.