Change date and time format via command prompt

Question

I was just wondering, in Windows 7 and above, is it possible to change the way dates and times are displayed via the command prompt? Yes, I'm in the U.S. but I like doing things the European way:

(In Clock/Language/Region)

Short Date: Set as "d/M/yyyy"

Long Date: Set as "dddd, d MMMM yyyy"

Short Time: Set as "HH:mm"

Long Time: Set as "HH:mm:ss"

Answer 1

Yes, it's possible e.g. using reg add command.
Check the HKEY_CURRENT_USER\Control Panel\International registry key:

reg query "HKCU\Control Panel\International"

For instance, query Short Time format:

reg query "HKCU\Control Panel\International" /V sShortTime

and set it to desired value:

reg add "HKCU\Control Panel\International" /V sShortTime /T REG_SZ /D HH:mm /F

If value name or data contains spaces, use double quotes (surrounding double quotes would not be written to registry):

reg add "HKCU\Control Panel\International" /V sShortTime /T REG_SZ /D "HH:mm" /F

A word of warning: Changing this registry value changes the settings in the user's profile, so it may have side effects in other areas. For example the way the clock is displayed in the task bar. And maybe it breaks other scripts that expect another time/date format.

So be careful when using this trick in something which you give to others!