On Wed, 10 Jan 2001, Guy Harris wrote:
> On Tue, Jan 09, 2001 at 03:27:08PM -0900, James A. Crippen wrote:
> > May I suggest the following minor changes to the manpage Synopsis section
> > for tethereal? (Haven't looked at ethereal's page yet.)
>
> It could use similar changes.
>
> > Change
> >
> > ... [ -f filter expression ] ... [ -R filter expression ] ... [ filter
> > expression ]
> >
> > to
> >
> > ... [ -f capture filter expression ] ... [ -R read filter expression ]
> > ... [ capture filter expression ]
>
> ...except that whether the last of those is a capture filter or a
> display filter depends on whether you specified a "-r" flag or not, i.e.
> whether you're doing a live capture or reading a capture file.
Ah, I didn't know about this. That's somewhat subtle. But it makes
sense.
> > which would make it more obvious that the default is a capture filter and
> > not a read filter,
>
> But that's the "default" only if no "-r" flag is specified; capturing
> rather than reading a capture file is the default, but just calling the
> command-line arguments "capture filter expression" might lead one to
> believe that it's *always* a capture filter expression, which it isn't.
>
> I've checked in changes to the Ethereal and Tethereal man pages, except
> that
>
> 1) I call the argument to "-R" a "display filter expression"
> rather than a "read filter expression", as the document
> refers to that type of filter as a display filter when it
> discusses the syntax;
>
> 2) it just says "filter expression" for the command-line filter
> expression in Tethereal, as per the above.
That sounds like a good solution. I didn't know about the -r option which
switches the meaning of the final argument. I think having both types of
filter expression labeled as such in the synopsis should point out that
there are different syntaxes and most people would keep reading a bit more
to figure out which one to use.
'james
--
James A. Crippen <james@xxxxxxxxxxxx> ,-./-. Anchorage, Alaska,
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