Get hostname in upstart script Ubuntu 14.04

hostname.conf

description "example hostname script"
author "Tim Simmons"

setuid bob

start on runlevel [2345]
stop on runlevel [!2345]

# retry if ended unexpectedly
respawn

# limit the retries to max 15 times with timeouts of 5 seconds
respawn limit 15 5

# Time to wait between sending TERM and KILL signals
kill timeout 20

script
    HOSTNAME=$(hostname -s)
    exec /path/to/app -n $HOSTNAME 
end script