What can lead to “IOError: [Errno 9] Bad file descriptor” during os.system()?

Question

I am using a scientific software including a Python script that is calling os.system() which is used to run another scientific program. While the subprocess is

Answer 1

You can get this error if you use wrong mode when opening the file. For example:

    with open(output, 'wb') as output_file:
        print output_file.read()

In that code, I want to read the file, but I use mode wb instead of r or r+