Accessing environment variables in Python created by C shell script

Question

I have some hard time to access environment variables in a Python script but those environment variables are created by a C shell script. To further elaborate my question, this is what I am doing:

call.subprocess(['csh_script_that_sets_envar_abc.csh'])

print os.environ.get("abc")

Result:

None

Why can't the C shell script set the environment in the Python script.

You can't. An environment variable is set for the current process & all subprocesses. You can't just set the environment of other random processes. You will need to communicate the value as output, or use some other form of IPC such as a socket. — Martin Tournoij
– Martin Tournoij, Commented Jul 30, 2015 at 20:37

Jonathan Leffler · Accepted Answer · 2015-07-30 20:40:05Z

2

Succinctly, there isn't a reasonable way for a child process (the C shell script) to set the environment variable in the parent process (the Python code). Child processes cannot affect the parent like that.

It isn't peculiar to Python or C shell per se; it is a property of parent and child processes on Unix-like systems.

answered Jul 30, 2015 at 20:40

Jonathan Leffler

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