python - Strange redirection effect with raw_input

Question

According to the manual, raw_input writes to stdout. I have this little program (test_raw_input.py):

# Test if rawinput writes to stdout or stderr
raw_input('This is my prompt > ')

And no matter how I run this:

$ python test_raw_input.py > xxx

or

$ python test_raw_input.py 2> xxx

The prompt always ends up in xxx. Why is this happening?

Answer 1

From your response to KennyTM I gather you understand

python test_raw_input.py > xxx

and it's only the second usage that you don't understand:

python test_raw_input.py 2> xxx

I think you are running into the behavior described here http://mail.python.org/pipermail/python-dev/2008-January/076446.html, which resulted in bug report http://bugs.python.org/issue1927, which has a comment saying it wasn't fixed yet last september.

However, there is a workaround: from https://groups.google.com/forum/?fromgroups=#!topic/chennaipy/R_VJYNdel-o, if you

import readline

before using raw_input, the behavior will be as you expect.