Parse installed packages from /var/log/apt/history.log

parse_history.log.py

#!/usr/bin/python3
import re
import sys

fileAPTHISTORY = sys.argv[1]

INSTALL_STRING = ('Install: ', 'Upgrade: ')
REMOVE_STRING = ('Remove: ', 'Purge: ')

pattern = re.compile('([a-z0-9-.+]+?):[a-z0-9]+? \(.+?\),?')

installed_packages_set = set()
removed_packages_set = set()

with open(fileAPTHISTORY, 'r') as file_handle:
    for line in file_handle:
        line = line.strip()
        if line.startswith(INSTALL_STRING):
            installed_packages_set.update(pattern.findall(line))
        elif line.startswith(REMOVE_STRING):
            removed_packages_set.update(pattern.findall(line))

installed_packages = list(installed_packages_set)
removed_packages = list(removed_packages_set)
installed_packages.sort()
removed_packages.sort()

print(' '.join(installed_packages))
print(' '.join(removed_packages))