[IPython-dev] what goes wrong with %%file

[Greg Wilson]

We just ran six Software Carpentry boot camps in a five-day period, and 
things largely went well --- most of our instructors are now using the 
IPython Notebook for all Python instruction, and learners are responding 
well.  One problem that did come up, though, is the behavior of 
'%%file'.  If I have a file called 'data.txt' on my hard drive, and put:

%%file data.txt

in a cell and then execute it, 'data.txt' is overwritten and the data is 
lost.  Everyone (including me, when I'm forgetful) expects this to load 
and display the existing file content if the file exists, just like an 
editor would.  I realize that it's problematic to have the in-cell 
display update automagically if and when the file is edited by some 
other tool, but "load if exists, create if not" seems like it ought to 
be straightforward.  Failing that, a prompt that says, "This exists, are 
you sure you want to overwrite it?" would be better than what happens now.

Thoughts?
Thanks,
Greg