Format date display / input, separate DAY, MONTH, and YEAR with hyphen ( - ) instead of slash ( / )

Hello everyone! When entering dates in LibreOffice (Ubuntu 16.04), it is much easier for me to use the subtraction symbol (-) as a separator for day, month and year since it is in a position on the keyboard (top right) which makes it unnecessary to look and search for the key, especially in my case that my fingers are a bit overweight … I have tried to customize the cell format but I don’t understand why it does not allow me to change from the symbol / to the hyphen, I’ve even looked in Preferences, but nothing … the custom format code I’m trying to add is: DDD D-MMM-YY. Thank you!

When entering dates … custom format code I’m trying to add is: DDD D-MMM-YY.

You can’t define allowed input format by defining a format. The only way to do such thing is by adding your own date acceptance pattern to Tools -> Options -> Language Settings -> Languages -> Date acceptance patterns: Add a D-M-Y here, enter as 28-1-2021 (e.g. for today) and format your cells as DDD D-MMM-YY

Note: To avoid changing Date acceptance patterns you could enter in ISO 8601 format using YYYY-MM-DD (eg. 2021-01-28) and using the format code DDD D-MMM-YY

> why it does not allow me to ...

Enter directly into field Format Code

... and please: Remove "all caps" from your title, which has a special meaning in internet netiquette.

Have you considered adopting the ISO-8601 format (YYYY-MM-DD) which is an international standard, universally recognized, unambiguous, readable by anyone (even when momentarily muddle-minded), and a generally Good Thing to do?

Opaque: Thank you! Sorry for the lack of etiquette, it won’t happen again
ve3oat: About the ISO-8601 format, considered and discarded. Thank you anyway

solved, thanks to Opaque