linux generic "mail" command cannot add custom headers?

[Nomen Nescio]

I want to add a custom header (e.g. "X-My-Custom-Header: my data") to
a message sent using the "mail" command.

I'm having a hard time seeing how this is done. No examples appear in
my web searches. The reference manual implies that one can hack a way
to do this by adding the line "~hX-My-Custom-Header: my data" to the
body of the message, and use the -I option to make a non-interactive
message appear interactive.

This approach is very sloppy, and more importantly, it doesn't work.
Some cryptic error appears.

What's the proper way to generate an e-mail from a script and add a
header field so that it can be filtered?

[Chris Davies]

Nomen Nescio <nob...@dizum.com> wrote:
> I want to add a custom header (e.g. "X-My-Custom-Header: my data") to
> a message sent using the "mail" command.

> I'm having a hard time seeing how this is done.

On my Debian system the first option presented from "man mail" gives an
appropriate solution. (On my system "mail" is linked via /etc/alternatives
to bsd-mailx. Your system may be different.)

If you really need a custom header, the truly generic solution is to
create enough of the headers to make a message that can be fed directly
to /usr/lib/sendmail:

FROM=chris-...@roaima.co.uk
TO=doc...@tardis.galifrey.kasterborous.piscescetus.glx
(
echo "From: chris <$FROM>"
echo "To: the doctor <$TO>"
echo 'Subject: key please'
echo 'X-My-Custom-Header: my data'
echo
echo 'Please can I have a key to your tardis'
) | /usr/lib/sendmail -f "$FROM" "$TO"

Chris

[Eli the Bearded]

In comp.mail.misc, Chris Davies <ch...@roaima.co.uk> wrote:
> Nomen Nescio <nob...@dizum.com> wrote:
> > I want to add a custom header (e.g. "X-My-Custom-Header: my data") to
> > a message sent using the "mail" command.
> > I'm having a hard time seeing how this is done.

The "mail" program could be a lot of things. Traditional "mail" might
be able to do it via crazy ~ commands, but "mailx" or "nail" has
likely fixed those issues (they can be used for security exploits in
some situations).

> If you really need a custom header, the truly generic solution is to
> create enough of the headers to make a message that can be fed directly
> to /usr/lib/sendmail:
> FROM=chris-...@roaima.co.uk
> TO=doc...@tardis.galifrey.kasterborous.piscescetus.glx
> (

...

Someone has already written a nice shell script that does this for
you. It's called "Rnmail" and it ships with trn. Just run it with
no arguments and it will prompt for To: and Subject: then dump you
in $EDITOR with fully modifiable headers.

> ) | /usr/lib/sendmail -f "$FROM" "$TO"

Although, as shipped Rnmail does not use -f to set envelope "From ".
It does use -t to read the recipients from the message, however.

I've hacked my version to add -f in, if I set From: in the message.
I use formail (from the procmail package) to extract the bare address,
since envelope "From " does not include a name field.

Here's what the "sendmail" state of the case statement looks like now:

case $mailer in
*sendmail)
# formail -X From: extract from header
# formail -rcx To: create a reply header, and then
# extract the value of the To: header
# tr -d ' ' remove whitespace
from=`formail -X From: <$tmpart |formail -rcx To: |tr -d ' '`
case "X$from" in
X) fromarg= ;; # no from available
X*) fromarg='-f "'"$from"'"' ;;
esac
echo "$mailer $fromarg -t <$tmpart"
$mailer $fromarg -t <$tmpart
;;

Elijah
------
has been using Pnews and Rnmail directly for years

[Anonymous]

Chris Davies <chris-...@roaima.co.uk> wrote:
>
> On my Debian system the first option presented from "man mail" gives
> an appropriate solution. (On my system "mail" is linked via
> /etc/alternatives to bsd-mailx. Your system may be different.)

I checked other systems, and noticed the "-a" option. But that's not
available on the (redhat) system I need it on.

> If you really need a custom header, the truly generic solution is to
> create enough of the headers to make a message that can be fed
> directly to /usr/lib/sendmail:

Thanks. That's what I ended up doing.