pycaesar

usage: caesar.py [-h] [-i INPUT] [-k KEY] [-o OUTPUT] [-d]

options:
  -h, --help            show this help message and exit
  -i INPUT, --input INPUT
  -k KEY, --key KEY
  -o OUTPUT, --output OUTPUT
  -d, --decrypt

python3 caesar.py -i input.txt -k key.txt 
IN:     Imi place sa mananc
OUT:    Iam dpegi se aebebg
KEY:    4 -> abcdefghijklmnop