Writing Your Own Draft Message Editor(s)
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You may want to do more than an editor like vi or emacs
can do to a draft message.
For instance, you might want to start prompter on the new
draft, then run a second editor to fill in the body.
Or you might want to do something automatically each time a
draft message is edited, like updating a mail message log.
Or you could customize the way that a particular MH program,
such as dist, handles a draft message.
These are all good reasons to write a special editing shell script.
There are five things to know before you write your editor script:
-
Each of the four mail composition commands will make a draft message for you.
If no other editor (including prompter) has touched it, the
draft will contain:
-
For comp, an empty copy of the components file.
(Exception: with comp -use, draft will be exactly as it
was left before.)
-
For repl, the result of the replcomps file, with the
original message filtered through the -filter file (if you used one).
-
For forw, a copy of the forwcomps file, with the forwarded
message(s) (filtered through -format or -filter if you used one).
-
For dist, a copy of the distcomps file.
For more information, see the Section
Making the Draft from the Template File.
-
The full pathname of the draft message will be in the $1 parameter.
-
You can use the environment variables listed in the
Table Environment Variables that MH Sets.
-
Your editor should save the edited draft in the same file ($1)
where it read the draft from.
-
If your editor exits with a zero status, whatnow will prompt the
user What now?.
But, as the Section
Aborted Draft Messages explains,
if your editor exits with a nonzero status, whatnow will abort
without sending the message, and:
-
If the mhuse variable is set to 1 (the comp -use
program is being used), your draft message won't be deleted.
-
Otherwise, the draft message will be deleted.
distprompter,
an editor shell script, acts like prompter
to read the message header of a message you're distributing with dist.
When it's done reading the header fields, it saves the draft and exits
without giving you a chance to type the body (you can't type a body for
dist).
Even if you don't run distprompter, it's a good example of what
you can do with an MH draft editor.
To run distprompter or another editor that you write, put an
entry like this in your MH profile:
dist: -editor distprompter
If you write a more general purpose shell script editor for all the MH
message composing programs, you can use an MH profile entry
like this instead:
Editor: myeditor
One more note about editors: even though the
mh-profile(5)
and whatnow(1) manual pages have a lot of details, they don't explain
an editor's environment or the effect of its exit status very thoroughly.
I wrote this little test editor script that helped me learn.
Maybe it'll help you:
#! /bin/sh
echo The environment of $0:
printenv
echo "Command line had: '$*'"
echo -n "Enter exit status for $0: "
read stat
exit $stat
Run it by typing, for example:
% comp -editor testedit
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