number_and_format.py

"""
Reads a filegiven as CLI arg, puts a number as prefix on each line
and adds the seperator between the lines.
"""

import sys

file_name = sys.argv[1]
f = open(file_name, 'r', encoding="utf8")
contents = f.readlines()
f.close()

sep = "\n\n===================================================================================\n"

for i in range(len(contents)):
    contents[i] = str(i + 1) + ". " + contents[i] + sep

file_contents = "\n".join(contents)
f = open(file_name, 'w')
f.write(file_contents)
f.close()