[IPython-user] passing negative float as arguments to a script

[Johann Cohen-Tanugi]

hi there,
I apologize for this horrendously trivial question but :
[cohen@jarrett ~]$ more testneg.py
import sys

if __name__=='__main__':
    print sys.argv[1]
    num=float(sys.argv[1])
    print "First arg is : %g"%num

gives me :
[cohen@jarrett ~]$ python testneg.py -1
-1
First arg is : -1
[cohen@jarrett ~]$ ipython
Python 2.5.1 (r251:54863, Jun 15 2008, 23:59:20)
Type "copyright", "credits" or "license" for more information.

IPython 0.9.0.bzr.r1016 -- An enhanced Interactive Python.
?         -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help      -> Python's own help system.
object?   -> Details about 'object'. ?object also works, ?? prints more.

In [1]: run testneg -1
-1
First arg is : -1

In [2]:
Do you really want to exit ([y]/n)?
[cohen@jarrett ~]$ ipython testneg.py -1
<long ipython help message>
WARNING:
Error in Arguments: "Illegal option '-1'"


So what should I do? I tried some sequences of quotes/double 
quotes/escape char without success.
thanks in advance :(
Johann