Windows 8/10 date format dd/mm/yyyy

You can use the GUI to set a custom date format for any given region:

1. Open the Region control panel (intl.cpl from a terminal).
2. Click Additional settings... at the bottom-right of the window.
3. The Customize Format window will appear, click the Date tab.
4. In the Short date field, enter your desired format. For example: d/M/yyyy.
5. Click apply, and the changes take effect immediately.