I was using [tee](http://man7.org/linux/man-pages/man1/tee.1.html) with a long running Python process, but I wasn’t seeing any output. This is a result of Python buffering the stdout stream. You can run force Python to run in unbuffered mode using the -u flag at the command line.

Force stdin, stdout and stderr to be totally unbuffered. On systems where it matters, also put stdin, stdout and stderr in binary mode.