Jupyter notebook command ignores --notebook-dir=C:\ #1291
Description
I was testing out the command to run jupyter notebook to serve notebooks from a specific directory. As a test, I was trying to serve from C:\ (this is clearly not a sensible place to serve from normally, but it was a quick and easy test). But the command ignored the --notebook-dir option and served from the current directory.
>jupyter notebook --notebook-dir=C:\
[I 11:05:43.435 NotebookApp] Serving notebooks from local directory: C:\Work\Scratch
[I 11:05:43.435 NotebookApp] 0 active kernels
[I 11:05:43.435 NotebookApp] The Jupyter Notebook is running at: http://localhost:8888/
[I 11:05:43.435 NotebookApp] Use Control-C to stop this server and shut down all kernels (twice to skip confirmation).
[I 11:05:58.443 NotebookApp] Interrupted...
[I 11:05:58.443 NotebookApp] Shutting down kernels
This is Jupyter 4.0.6, on Windows 7, using Python 3.5.1 64-bit (python.org version).
It appears to only be C:\ that has this behaviour - other directories work fine with or without a trailing backslash, and with back or forward slashes. Also, C:/ works as expected. Oddly, even using D:\ works, so it's somehow specific to the C drive.
It's clearly a very minor corner case, but I wasted quite some time working out what was going on.