This is something that can be answered only by people who can read the source
code, so I hope one of you can help me out.
I wondered whether the following would work with formail 3.11pre4, and it
did (an example, not the actual command):
formail -R Re Foo:
It renames all headers whose names start with "Re" -- Reply-To:, Received:,
Return-Path:, Return-Receipt-To:, Really-Insignificant:, Retch-On-Sight:,
whatever -- to "Foo:", keeping their contents intact as formail -R does when
the old name is fully specified through the colon. And it properly replaces
the entire name, not just the initial part specified.
That feature can be very useful to me.
formail is supposed to honor partial field names for -X and -x, and for the
forms of -I and -i where you don't specify a new value (where you use -I to
delete the header line or -i to change its name to Old-originalname:). That
facility will not go away.
Now I need to find out whether what I just discovered above about formail -R
will work in future releases. Only Stephen knows that for sure. I wrote to
him but he (unsurprisingly) has yet to respond.
So this is my question for those who can read the source: how difficult would
it be to make formail -R partialheader newname: *stop* working? In the opin-
ions of those of you who can understand the source code well enough to form
opinions, is it so intricately entangled with the code for documented fea-
tures that I can rely on using it in future releases, or is it some easily
fixed mistake that might very likely get cleaned up?