#!/bin/bash
# avpkstacking.bash AV+PKstacking of jpg files in this folder

FILE_LIST=$( ls -tr *jpg | tail -99 | sed ':a;N;$!ba;s/\n/ /g' )
# ls lists files in directory sorted jpg and reversed in time (-tr)
# tail -99 is only the last 99 files
# sed ... removes the newlines between file names, all is on one single line

# Print some data to the output screen
echo $FILE_LIST
echo "WAIT"

# ImageMagic average stack
convert $FILE_LIST -average aaa-av.png
echo "average stack aaa-av.png ready"
echo "WAIT"

# ImageMagic peak stack
convert $FILE_LIST -background black -compose lighten -flatten aaa-pk.png
echo "peak stack aaa-pk.png ready"
echo "READY"

sleep 10  # If you want the terminal screen 10 seconds open when finished
exit 0

#######################
#     EXPLANATION     #
#######################
# Copy this bash file "avpkstacking.bash" to the folder with the jpg.files
# THE FOLDER SHALL ONLY CONTAIN THE JPG FILES YOU WANT TO USE FOR THE STACKING 
# All jpg files till a maximum of 99 will be stacked to an average and peak picture
# If you want to use less recent jpg files, change the -99 to the value you want
# For example: -24 for an 8 hour time period and 20 minute grabs
# The results will be in aaa-av.png and aaa-pk.png
# As it are png files, they are not part of the stacking file list
# IMPORTANT! SET THE PROPERTIES OF THIS BASH FILE TO: Permissions --> Execute --> Anyone!
#######################