[PATCH] sed: Document POSIX -E sed flag that selects EREs (as a synonym for -r)

[David A. Wheeler]

On Wed, 30 Oct 2013 12:57:06 +0100, Denys Vlasenko <vda.linux at googlemail.com> wrote:
> busybox is about small size.
> Is there any use for the consumer of --help output to see
> "(same as -E for backwards compatibility)" text?

That's droppable.

> This is what I'm going to do:
> 
> -r,-E   Use extended regex syntax

I'd prefer listing "-E" first (since that's the POSIX flag),
but otherwise that's great by me.

> > -               "regexp-extended\0" No_argument         "r"
> > +               "regexp-extended\0" No_argument         "E"
> 
> Does it change any visible behavior?

If you generate docs from this code, then I'd like
"regexp-extended" to say it's the same as "-E", not "-r".
Other it's the same.

--- David A. Wheeler