Shell script output in monit alert

[Rowan Wookey]

Hi,

Does anyone know if it's possible to have the output of a shell script appear 
in a monit alert. I've tried adding this

set alert address@hidden with mail-format {
     message: Monit $ACTION $SERVICE at $DATE on $HOST: $DESCRIPTION.
            Yours sincerely,
            monit
                `free -m`
 }


But that doesn't execute the `free -m`

Regards

Rowan