still.sh

#!/bin/bash
#
# takes 3 pictures, 20 seconds apart.

function check {
		# Certain conditions cause raspistill to lock up, primarily if it has trouble writing the image to storage.
		# Since we store locally now (we didn't use to) it's not such a problem
		# but if you're saving direct to NFS or CIFS these checks are important.
        PID=$(ps ax | grep raspistill | grep -v grep | awk '{print $1}')
        if [[ ! -z "$PID" ]]; then
				# Already running, try to kill it
                echo "Running, pid: $PID"
                kill $PID
                sleep 1
        fi
        PID=$(ps ax | grep raspistill | grep -v grep | awk '{print $1}')
        if [[ ! -z "$PID" ]]; then
				# Still running, exit with error
                echo "Kill failed: $PID; Exiting"
                exit 1
        fi
}

function shot {
		# Check raspistill isn't already running
        check
		# Take a picture and save it using a timestamp as the file name
		# YearMonthDayHourMinuteSecond.jpg, eg 20140515113500.jpg
        raspistill -w 1920 -h 1080 -o /home/pi/temp/`date +'%Y%m%d%H%M%S'`.jpg &
}

shot
sleep 20
shot
sleep 20
shot