Sleep the Display if the user has been Idle for 30 minutes or more. Required: OS X 10.9+

idleSleepDisplay.sh

#!/bin/sh

###########################################
##
##  Name:         idleSleepDisplay.sh
##
##  Description:  Sleep Display if Idle
##  Author:       James W Mann <me@jameswmann.com>
##
##  Notes:        Minimum Idle time is set for 30 minutes ( 1800 seconds ) by default.
##                Change MINIDLE to your desired wait period, in seconds.
##
##  Requirements: OS X 10.9+
##
###########################################

# Define the minimum amount of Idle time (in seconds) to be considered no longer active
MINIDLE=1800

# Grab the system defined Idle time and convert it to seconds
# Source: https://www.dssw.co.uk/blog/2015-01-21-inactivity-and-idle-time/
IDLETIME=$((`ioreg -c IOHIDSystem | sed -e '/HIDIdleTime/ !{ d' -e 't' -e '}' -e 's/.* = //g' -e 'q'` / 1000000000))
echo "$0: Idle for $IDLETIME seconds.";

if [ $IDLETIME -lt $MINIDLE ]; then
    echo "$0: Aborting, User is currently using the computer."
    exit 1
fi

echo "$0: User is Idle, Sleeping Display..."
# This command only works in OS X 10.9+
# Source: http://apple.stackexchange.com/a/110137
pmset displaysleepnow

# Great Success!
exit 0