time_convert.py

time_convert.py

#!/usr/bin/env python

import sys
import fileinput
import re

diff = -8

def repl(matched):
    h = int(matched.group(1)) + diff
    prefix = '↩︎ ' if h < 0 else '↪︎ ' if h >= 24 else ''
    return f'{prefix}{h % 24:02d}:{matched.group(2)}'

for line in fileinput.input():
    sys.stdout.write(re.sub(r'(\d+):(\d\d[^\d])', repl, line))