在C Shell脚本创建的Python中访问环境变量

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.

Answer 1

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.