python - How to handle random bytestream when executing shell commands?

Question

I want to run arbitrary commands in the shell and get stdout and stderr, for example like this:

cmd = subprocess.run(command, shell=True, universal_newlines=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
stdout = cmd.stdout
stderr = cmd.stderr

However, stdout and stderr might contain random bytestreams. This leads to errors like this:

UnicodeDecodeError: 'utf-8' codec can't decode byte 0xfd in position 135: invalid start byte

How can I handle this? Stuff like ? would be ok as result.

Answer 1

This error is caused by universal_newlines=True causing your data to be read as text rather than as binary content. Remove that argument.