environment variables in xp 1

[tomk01]

I need to create and use a variable in a batch file to rename a file. I don't know what command to use to set the variable.

 

[bcastner]

SET

e.g.
To create and use a new variable:
set bcastner=test
echo %bcastner%
test

To use existing variables:
set bcastner=%windir%%
echo %bcastner%
C:\WINDOWS