Instructions for running can be found in the file. From the file:
# To run: in the terminal, type ./redgreencount.tcl [nameofdirectory]
# To make a CSV file for excel: ./redgreencount.tcl [nameofdirectory] > out.csv
# You can also plumb multiple directories by ./redgreencount.tcl foo bar etc
#
# This will plumb the directory, and for each subdirectory containing
# images (tif, jpeg or ppm,) it will return the total intensity of
# redness, greenity and bluetitude over all the images in that one
# directory. The CSV output lists the directory path, directory name,
# number of images, then the sum of red, green and blue intensity.