Code reuse in Windows scripts

[DayLaborer]

I have a command file that contains the following lines of code:

Set mm=%date:~4,2%
Set dd=%date:~7,2%
Set yy=%date:~-2%
set filename=ANX-1-%mm%%dd%%yy%-1

We need to use similar code in many different command files. What is the best way to reuse the code?

Thanks!