UNIX for Dummies Questions & Answers

#! /bin/bash
#This script monitors local network via snmp
# accesslist is a txt file that sed uses to change the MAC addresses into the device name
# it notifies me via growl and displays with geektool
d=$(snmpwalk -v 2c -c publicpassword -M /usr/share/snmp/mibs:$HOME/share/mibs -m+AIRPORT-BASESTATION-3-MIB 10.0.1.1 dhcp \
| sed -f /Users/user/Documents/bin/accesslist \
|sed 's/AIRPORT-BASESTATION-3-MIB::dhcpLeaseTime.//' | awk ' $4 >= 1036600 { print $1 }')
if [ ! -n "$d" ] ; then
echo "No New Connections"
else
echo " "$d" has renewed
it's lease"
        if [ "$d" -ne ""iPhone"" ]
        then
growlnotify  -m " "$d" has just renewed it's lease" -a "Airport Utility" -n "NetWatch" -t "New DHCP Lease"
fi
fi
# I don't want a notification every time my iphone's display wakes up. it reconnects to the wifi so I added a second if statement