some kind of referance exist, but not during batch command.

I have a txt file, with the old username and the new ones , with the following format:
abt,adam.bertil
dfp,david.filip
egv,erik.gustav
Can I get the value "abt" to be ex a$ then make adam.bertil to be b$
Then make the copy
Code:
 copy 'a$' 'b$'



???

\erik