Extension Attribute to check for Whitelisted Netboot server

After upgrading to 10.11 on campus we wanted to find out which machines need our netboot server whitelisted to allow for booting remotely. I put together this quick EA that others may find useful.

#!/bin/sh

osvers_major=$(sw_vers -productVersion | awk -F. '{print $1}')
osvers_minor=$(sw_vers -productVersion | awk -F. '{print $2}')

# Checks to see if the OS on the Mac is 10.x.x. 
if [[ ${osvers_major} -ne 10 ]]; then
  echo "Unknown Version of Mac OS X"
fi

# Checks to see if the OS on the Mac is 10.11.x or higher.
if [[ ${osvers_major} -eq 10 ]] && [[ ${osvers_minor} -lt 11 ]]; then
  echo "System Integrity Protection Not Available For `sw_vers -productVersion`"
fi

if [[ ${osvers_major} -eq 10 ]] && [[ ${osvers_minor} -ge 11 ]]; then
    # Checks System Integrity Protection status on Macs
    # running 10.11.x or higher
    SIP_status=`/usr/bin/csrutil status | awk '/status/ {print $5}' | sed 's/.$//'`
    # If it's disabled, just print disabled
    if [[ $SIP_status == "disabled" ]]; then
        echo "<result>SIP Disabled</result>"
        # if it's enabled, we'll get the netboot list
    elif [[ $SIP_status == "enabled" ]]; then
        netbootList=`/usr/bin/csrutil netboot list`
        echo "<result>$netbootList</result>"
    fi
fi