In OS/2, the first line of a REXX program must start with a comment in column 1. This tells OS/2 your program is written in REXX, and not its built-in Batch facility. Both Batch facility and REXX programs can use the file name extension CMD. Each requires its own special processing, so OS/2 checks the first line to see which type of program it is. If it finds a REXX comment, the program is processed as REXX. Use /* and */ to mark the start and end of a comment:
/* This is the required column-1 comment. */ say ... /* This is a comment on the same line as an instruction */ /* Comments may occupy more than one line. */ /************************************* * Comments may be boxed as headers: * * * * HELLO.CMD written by J. Smith * * November 15, 1994 * * A program to greet a user by name. * *************************************/
For a column-1 comment it is enough to use /* */, but more often one uses this space to give a brief description of the program.
When REXX finds a /*, it stops interpreting the program until a */ is found, which may be a few words or several lines later.