Simple python script to make a list of all the filenames in a particular folder tree.

list_filenames.py

import os
with open('output.txt', 'w') as a:
	for path, subdirs, files in os.walk('/folder/with/files'):
		for filename in files:
			filestr = str(filename)
			if filestr.endswith('.htm') or filestr.endswith('.html'):
				print(filename)
				a.write(str(filename) + ',') #separate by comma
			else:
				print('Skipping non html or htm file:' + filestr)