[RFC] perf script: modify field selection option

[Stephane Eranian]

Hi,

I have been using the perf script -F option on the latest perf and I
find it not very convenient to use. I appreciate the + and - prefix to
field names to add or suppress them. But most of the time, I want to
print only one or two fields and I have to guess which ones are there
by default so I can suppress them. I think there should be a way to
say: start from no fields. I understand why you have default to
maintain compatibility with older perf script but I would like a
syntax to say: remove defaults. For instance:

$ perf script -F --,+ip,+syms .....

Where -- would mean drop all defaults.

Any better suggestions?