ipython/ipython — pull request #2329 by bfroehle (2012-08-23 18:28:35+00:00)
Title: Better error messages for common magic commands.

Print a helpful message when the user calls a magic command with a missing argument, rather than a long traceback.

In addition, I have removed the 'protected' magic list from qtconsole .. these are the magic whose name shows up like `%load?`. I think it's visually confusing to have some magics show up with a question mark, and it seems irrelevant if running the magic command prints a short usage error message. One small issue is this might prevent the discovery of the `%magic?` syntax for getting help. Perhaps we should catch `UsageError` in `run_line_magic` and `run_cell_magic` and suggest the user run `%{magic_name}?` for help.