echo "somecommand -someOptions 2>&1 | mail -s "$HOST after reboot: somecommand -someOptions" my.mail@address.com" | at now +5 minutes ;
#do admin stuff before reboot in less than 5 mins here ;
touch /fastboot ; reboot

echo "echo "somecommand -someOptions 2>&1 | mail -s \"$HOST after reboot: somecommand -someOptions\" my.mail@address.com" | at now +5 minutes ;
#do admin stuff before reboot in less than 5 mins here ;
touch /fastboot ; reboot ; " | at now + 1 minute

at now + 1 minute <<!
echo "somecommand -someOptions 2>&1 | mail -s "$HOST after reboot: somecommand -someOptions" my.mail@address.com" | at now +5 minutes
#do admin stuff before reboot in less than 5 mins here
touch /fastboot ; reboot
!

at now + 5
/home/user/bin/doit
^D