If you have a command macro file named MACRO_FILE.PCM you can execute this file with the command @MACRO_FILE If you have a command macro file named MACRO_FILE.PHYSICA you can execute this file with the command @MACRO_FILE.PHYSICA or EXTENSION `PHYSICA' followed by @MACRO_FILE You can also use text variables, for example: T=`MACRO_FILE' EXTENSION `PHYSICA' @T