Seeing escape characters when pressing the arrow keys in python shell

On OS X, Xcode updates sometimes break readline. Solution:

brew uninstall readline
brew upgrade python3
brew install readline
pip3 install readline

If the problem still persists, try to remove readline using pip and install it using easy_install:

pip3 uninstall readline
easy_install readline

On OS X, I have different problem.

When I using system python shell, the keys is no problem, but problem in virtualenv. I'd try to reinstall/upgrade virtualenv/readline and nothing fixed.

While I try to import readline in problem python shell, get this error message:

ImportError: dlopen(/Users/raptor/.virtualenvs/bottle/lib/python2.7/lib-dynload/readline.so, 2): Library not loaded: /usr/local/opt/readline/lib/libreadline.6.dylib
Referenced from: /Users/raptor/.virtualenvs/bottle/lib/python2.7/lib-dynload/readline.so
Reason: image not found

Cause there is /usr/local/opt/readline/lib/libreadline.7.dylib but not libreadline.6.dylib, so I make a symbol link:

ln -s libreadline.7.dylib libreadline.6.dylib

Problem has been solved!

I've solved this issue by installing readline package:

pip install readline