Sample of how to delete files from dir1 that doesn't exist in dir2 - Answer to post: https://www.facebook.com/groups/mac.israel/permalink/2941748212604513/

compfiles.py

#!/usr/bin/env python

import os
import sys

dir1_list = os.listdir('dir1') # Directory with many files
dir2_list = os.listdir('dir2') # Directory with duplicates of dir1 and maybe others
delete_list = []
for filename in dir1_list:
    if filename in dir2_list:
        #print ("File {} exists in both directories".format(filename))
        pass
    else:
        #print ("File {} DOES NOT exist in both, will be deleted from dir1".format(filename)) 
        delete_list.append(filename) # Deletes all files in dir1 that doesn't exist in dir2


for filename in delete_list:
    os.remove('dir1/{}'.format(filename))

genfiles.py

#!/usr/bin/env python

import os
import sys

os.mkdir("dir1")
os.mkdir("dir2")
for num in range(1000):
    filename = "file-{}.txt".format(num)
    with open('dir1/{}'.format(filename),'a') as f:
        f.write("File content of {}".format(filename))
    if (num % 5 == 0):
        with open('dir2/{}'.format(filename),'a') as f:
            f.write("File content of {}".format(filename))