cmd.exe: complex conditions?

Question

in DOS batch files, In an IF statement, is it possible to combine two or more conditions using AND or OR ? I was not able to find any documentation for that

Answer 1

AND:

IF  IF  ACTION

OR:

(SET _=) & (IF  (SET _= ) ELSE IF  (SET _= )) & IF DEFINED _ ACTION

For implementing OR this way, you do need command extensions.