Recover Git tags from commit messages

retag.py

#!/usr/bin/env python3

import subprocess

command = 'git log --oneline | grep "^[0-9a-f]\{1,7\} v[0-9\.]*$"'
output = subprocess.check_output(command, shell=True).decode('utf-8')

for line in output.splitlines():
  commit, tag = line.split()
  subprocess.call('git tag -a %s -m %s %s' % (tag, tag, commit), shell=True)