I can't use IPython on ep.io because the home folder there is read-only.
Please make IPython gracefully degrade when it can't write to ~/.ipython, instead of just giving up and exiting.
What version are you trying with? It should detect that ~/.ipython isn't writable, and use a temporary directory instead. But maybe that fails if your home directory is also read only.
Note that you can also set the environment variable IPYTHON_DIR to point to any location you want, in case you can't update ipython. Let us know if that works...
just to be specific: the fix is only in master, not 0.11 or earlier.
Note that IPython will still not be able to start if tempfile.mkdtemp() fails, but that should only happen if you have no access at all to the filesystem.
Closing as a duplicate of #669.