Make variable from Python file available on command line

Question

I have a small Python file from a third-party package with

$ cat a.py
a = 3.14

I would now like to make the value of a available on the command line. I initially thought that I just grep/sed/awk my way out of this, but perhaps there's a more pythonic approach.

Any hints?

You say it's third party but I don't understand why that stops you from adding code to it. — Alex Hall
– Alex Hall, Commented May 28, 2016 at 11:19
I have to fetch the source from upstream regularly and I need a clean source after reading the version. Perhaps one could programmatically insert code, execute, and remove the code again, but a little over-the-top. — Nico Schlömer
– Nico Schlömer, Commented May 28, 2016 at 11:24

Alex Hall · Accepted Answer · 2016-05-28 11:36:05Z

3

Here's a simple crude solution:

$ cat a.py
a = 3.14
a *= 2
$ python <(cat a.py && echo '\nprint(a)') 
6.28

There are various ways this might not work, but the constraints of your situation are not clear.

The \n is there to prevent a syntax error in the case that a.py does not end in a newline.

edited May 28, 2016 at 11:36

answered May 28, 2016 at 11:26

Alex Hall

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