A bash script to take screenshot every 60 seconds and then add a timestamp to it. Useful for creating time-lapse videos.

timed_capture.sh

#!/bin/sh
# Help from http://dptnt.com/2009/08/add-date-time-stamp-to-jpeg-photos-using-free-software-mac-linux-nix-edition/
# install the LCD font - http://www.dafont.com/digital-7.font
# install imagemagick via homebrew
# Install Time Lapse Assembler to make the movie - http://www.dayofthenewdan.com/projects/time-lapse-assembler-1/

set -e

font="$HOME/Library/Fonts/digital-7 (mono).ttf"
outputfolder="$HOME/Downloads/caps"

# Format is x,y,width,height. Origin is the upper-left corner
rect="403,94,1061,1026"

delay=2
fontFill="black"

################################################################
mkdir -p ${outputfolder}

while [ 1 ];do
  date=$(date +%d\-%m\-%Y\_%H.%M.%S)
	file="/tmp/${date}.png"
	screencapture -t png -R${rect} -x ${file}

	output="${outputfolder}/${date}.png"

	# Get the file dimension
	dim=$(identify -format "%w %h" "$file")
	width=${dim%% *}
	height=${dim#* }

	# file date
	MODDATE=$(stat -f "%Sm" $file)

	# Decide the font size automatically
	if [ $width -ge $height ]
		then
		pointsize=$(($width/30))
	else
		pointsize=$(($height/30))
	fi

	echo "Writing file: $output"
	convert "$file" -gravity SouthEast -font "$font" -pointsize $pointsize -fill ${fontFill} -annotate +$pointsize+$pointsize "${MODDATE}" "$output"

	rm ${file}

	sleep ${delay}
done

exit 0