email-reminder

email-reminder

#!/bin/bash -e

perr(){
  echo "$@" > /dev/stderr
}

usage(){
  perr "Usage: cat <email> | email-reminder <at(1)-arguments>*"
  perr "$@"
  exit 1
}

timespec="$1"
shift || usage "missing argument"
[ ! -z "$EMAIL" ] || usage "EMAIL is undefined (example john.doe@example.com)"
[ ! -z "$FULLNAME" ] || usage "FULLNAME is undefined (example John Doe)"

fields=$(grep -Ei '^(Message-ID:  *<.*> *|Subject: .*)$')
export messageid=$(echo "$fields" | grep -i '^Message-ID' | grep -oi '<.*>' | head -n 1)
export subjectline=$(echo "$fields" | grep -i '^Subject' | head -n 1)

if [ -z "$SENDMAIL" ]; then
  SENDMAIL='msmtp -t --read-envelope-from'
fi

at $timespec <<EOS
date=\`date +'%a, %d %b %Y %T %z (%Z)'\`
salt="$timespec $EMAIL $FULLNAME \$messageid \$date"
echo "From: $FULLNAME <$EMAIL>
To: $FULLNAME <$EMAIL>
\$subjectline
Message-ID: <\`echo "\$salt" | md5sum | cut -d' ' -f1\`@email-reminder>
Date: \$date
In-Reply-To: \$messageid
References: \$messageid

Reminder!" | $SENDMAIL
EOS