Edit: You should have a look at msmtp-queue-scheduler to solve this :-)

Thanks Nicolas!

I've been looking for a solution to this problem:

Sometimes, I just sent an email, and after 10 seconds I realise: “Oh, damn, I forgot to add something!” or “Oh, nooooes, I sent it to the wrong person!” Whatever. This is annoying.

Making mistakes is human. Email clients are for humans, therefore they should be able to cope with our mistakes and help fix them. That's why software should allow us to “undo” or “cancel” our actions.

Gmail does this right, so why can't we do it in Mutt too?

I wrapped my head around this a little bit. And I'm no programmer, so after trying to add some stuff here and there, I finally decided to have it with this very, very, very dirty hack. You've been warned. So here's how I do it:

  • I use the msmtpq script which allows me to queue emails when I'm offline, so that msmtp can take care of sending queued email when I'm back online.

  • I have tried to put a delay of 30 seconds any time before calling msmtp or I tried to force msmtpq to queue all outgoing email for at least 30 seconds. But I couldn't make it work. So instead,

  • I added sleep 30 && at the beginning of the msmtpq script!

  • Result: now when I send an email, I have 30 seconds to realise when I made a mistake. Then, I just need to activate plane mode on my laptop, and fix whatever needs fixing from here.

    One issue with this workflow is that I can't just edit the outgoing email, I also have to make sure I update the openPGP signature. So I'd probably just delete the email and start again from Mutt.

I warned you, this is very ugly :-)

But as they say: the best way to get an answer on the net is not to ask a question, but to give the wrong answer!

So if anyone wants to implement this feature in msmtpq, that would be great. Here's how it could work ideally, in the .muttrc:

set sendmail="msmtpq --wait 30" 
set sendmail_wait=-1  #send in the background

then msmtpq could queue the email for 30 seconds before testing the connection and feeding the email to msmtp. The Queue management could then allow the user to pause all outgoing emails, cancel the email containing the mistake, then sending remaining emails from the queue.

The msmtpq script is available at: http://sourceforge.net/p/msmtp/code/ci/master/tree/scripts/msmtpq/