Min-Max file dates in directory

minmax.py

import os, sys, datetime

maxm = minm = None
for root, dirs, files in os.walk(sys.argv[1] if len(sys.argv) > 1 else '.'):
    for name in files:
        path = os.path.join(root, name)
        mtime = os.path.getmtime(path)
        maxm = maxm if maxm and maxm > mtime else mtime
        minm = minm if minm and minm < mtime else mtime

def ftime(secs):
    return datetime.datetime.fromtimestamp(secs).strftime('%Y-%m-%d')
    
print ftime(minm), ftime(maxm)