Shell Programming and Scripting

I have written a script that will email a generic user when a device is "offline". I would like to enhance this by having the script lookup a contact's email and automatically add it to the MAIL_LIST. I am trying to lookup and return data based on a field common in two files

File 1 /optim/ais_scripts/files/offline/offline_readers.txt:
0150 PU SA Handheld 200-03

File 2 ; /optim/ais_scripts/files/bb_unit_contacts.txt
0150,contact name,contact@princeton.edu

#This script will email ais psig group any Active and Offline readers by loop and reader address, location number, location name.
#
#SCRIPT:mail_offlines
#
#revised:5/23/2008 dtierney
#
MAIL_FILE=/optim/ais_scripts/files/offline/offline_readers.txt

MAIL_LIST="generic_user@princeton.edu"

/optim/bin/read_shm > /optim/ais_scripts/files/offline/readers.status

rm /optim/ais_scripts/files/offline/offline_readers.txt

echo " LOC# Reader Name LP#-AD" >> /optim/ais_scripts/files/offline/offline_readers.txt
echo "----------------------------------------" >> /optim/ais_scripts/files/offline/offline_readers.txt
for j in `/optim/bin/parse_shm | grep "ACTIVE Off-Line" | awk '{ print substr($0,1,6) }'`
do
cat /optim/ais_scripts/files/offline/readers.status | grep "$j" | awk '{ print substr($0,15,4) substr($0,32,31) substr($0,1,6) }' >> /optim/ais_scripts/files/offline/offline_readers.txt
done
echo "------------------------------------------------------------------">> /optim/ais_scripts/files/offline/offline_readers.txt
mailx -s "Offline Readers" $MAIL_LIST < $MAIL_FILE
rm /optim/ais_scripts/files/offline/offline_readers.txt
echo "email has been sent"