What does :/= mean in %date:/=%?

Question

While searching for a way to create a date-named directory in Windows, I came accross this question with that accepted answer.

There's a comment below the accepted answer:

To make it more easy: mkdir %date:/=%

So, %date% prints the current date, but what does :/= do?

Answer 1

It means substitute for the string between the : and the = with the string after the = and before the closing %

So it strips out any / from the variable %date% which is set by default to the current date.

Answer 2

The form of the command is

%variable:text=replace%

and it removes text and inserts replace in the same spot.

In your case the replace is empty so it just removes any / characters from the date string.