Shell Programming and Scripting

#!/bin/bash

device="some name"
d=`date +"%m-%d-%Y"`
t=`date +"%T"`
voltageraw=`snmpget -v 1 -c blah 192.168.1.2 .1.3.6.1.4.1.14988.1.1.3.8.0`
voltage=`echo $voltageraw | tail -c 4`
voltfinal=$(awk -v temp=$voltage 'BEGIN { print (temp / 10) }')
tempraw=`snmpget -v 1 -c blah 192.168.1.2 .1.3.6.1.4.1.14988.1.1.3.10.0`
temp=`echo $tempraw | tail -c 4`
tempfinal=$(awk -v temp=$temp 'BEGIN { print (temp / 10) }')
tempf=`expr 9 / 5 '*' $tempfinal + 32`

thresh=23
if (( $(echo "$voltfinal < $thresh" | bc -l) )); then
        ## compile and email voltage history
        echo "Most recent voltages, last 10 samples." > /usr/src/includes/volt.txt
        echo "Samples are taken 15 minutes apart" >> /usr/src/includes/volt.txt
        echo "..." >> /usr/src/includes/volt.txt
        cmd="SELECT voltage FROM devices WHERE device_name='name' ORDER BY id DESC, time DESC LIMIT 0,10"
        mysql --user=monitor --password=blah monitor --host=localhost -e "$cmd" >> /usr/src/includes/volt.txt
        awk 'BEGIN{print "Subject:Voltage = '$voltfinal' VDC\nFrom:Voltage Tracker <me@whatever.com>"}{printf("%s\015\n", $0)}' /usr/src/includes/volt.txt | sendmail -t me@whatever.com
fi;
## put it all in a database
echo "INSERT INTO devices (DEVICE_NAME,DATE,TIME,VOLTAGE,TEMP) VALUES ('$device', '$d', '$t', '$voltfinal', '$tempf');" | mysql -u monitor -p blah monitor;

export PATH=${PATH}:/bin:/usr/sbin

tempf=`expr 9 '*' $tempfinal / 5 + 32`