When is Patch Tuesday?

Microsoft releases updates on a predictable cadence. The second Tuesday of every month is called “Patch Tuesday”.

There aren’t any Linux distributions (that I’m aware of) that have a similar release cadence. Package updates are released pretty much as soon as they are ready. Theoretically, you could check for updates every day and always have new updates to install each day.

However, if you have decided for one reason or another to just standardize your Linux patching around Microsoft’s patch release dates, then you will need a good way to figure out when the next Patch Tuesday will occur.

Python Script to get the second Tuesday of the month

I spent a lot of time searching the web for ways to list out all the Patch Tuesdays for a given year, and I didn’t find anything that worked well for me so I wrote this little python script to help with scheduling.

    #!/usr/bin/env python3
    import calendar
    import datetime
    import argparse

    # get the current year
    now = datetime.datetime.now().year

    parser = argparse.ArgumentParser(description='Get patch tuesday for a given year. Current year by default.')
    parser.add_argument('year', nargs='?', help='The year, example 2020', default=now, type=int)
    args = parser.parse_args()

    for month in range (1,13):
        cal = calendar.monthcalendar(args.year, month)
        # Second Tuesday will be in the second or third week of the month
        week2 = cal[1]
        week3 = cal[2]

        # Check if Tuesday is between 8 and 14. If so Second tuesday is in week 2. Else it's week 3
        if week2[calendar.TUESDAY] >=8 <=14:
            patchday = week2[calendar.TUESDAY]
        else:
            patchday = week3[calendar.TUESDAY]
        print(calendar.month_name[month], patchday, args.year)

Example output:

When you run the script with no arguments it prints all the second Tuesday’s for the current year:

    ./patch_tues.py
    January 14 2020
    February 11 2020
    March 10 2020
    April 14 2020
    May 12 2020
    June 9 2020
    July 14 2020
    August 11 2020
    September 8 2020
    October 13 2020
    November 10 2020
    December 8 2020

When you specify a year it will print the second Tuesday of each month for the specified year:

    ./patch_tues.py 2023
    January 10 2023
    February 14 2023
    March 14 2023
    April 11 2023
    May 9 2023
    June 13 2023
    July 11 2023
    August 8 2023
    September 12 2023
    October 10 2023
    November 14 2023
    December 12 2023

Note to the Pythonistas out there.

I know that this code isn’t very “pythonic”. But it works. I’d love to hear any suggestions you might have on how to make it better. If you want to make any suggestions or improvements check out the git repo: https://github.com/thegreatluke/get_patch_tuesday/blob/master/patch_tues.py

If you found this helpful, I’d love to. hear about it. Thanks for reading.

A Bash variation

Robert Mesibov, at Datafix has also written a good Bash script to help you track down patch Tuesdays. Check it out here: https://www.datafix.com.au/BASHing/2020-03-25.html