After some researches, it occurs that even if I can find some talks about multiple actions when restarting a service, it also seems it it not really possible to achieve :
if failed port 80 and protocol http then exec /home/sweet/script.pl and restart
When declaring the restart command for a service in the
monitrc configuration file, is it ok to try something like this :
restart program = "perl /home/sweet/crazy-stuff.pl && /etc/init.d/server restart"
monit -t don't mention any error I prefer to ask before to do bad things.