Disassemble a Python script from the command line?

November 10, 2021

In gcc you can use -S to stop compilation after your code has been compiled into assembly. Is there a similar feature with Python/bytecode? I know of ways like:

import dis
x = compile('print(1)', '', 'eval')
dis.dis(x)

Which prints:

  1           0 LOAD_NAME                0 (print)
              2 LOAD_CONST               0 (1)
              4 CALL_FUNCTION            1
              6 RETURN_VALUE

But I’m thinking of something more along the lines of:

> python3 -{SOME FLAG HERE} output my_script.py

Which outputs a file containing the scripts bytecode in a readable format.

>Solution :

If what you are looking for is the output of the disassembler, then you can run the module as a script:

python -m dis myscript.py

And the disassembler output will be printed to the standard output. You can use the appropriate shell tools to redirect that to some file. E.g. on *nix:

python -m dis myscript.py > output.txt

Caution: this use of dis is not documented as far as I am aware, and checking the source code it may not be a stable part of the module, but it does work for current CPython.