A command is a word, phrase, or abbreviation that tells the system to do something. In REXX, anything that is not a REXX instruction, assignment, or label is considered a command. For example, you can use OS/2 commands such as COPY, BACKUP, PRINT, TYPE, and so on in your procedures.
Here is an example of using the OS/2 command, TYPE, in a REXX procedure:
/* Issuing commands in REXX */ TYPE hello.cmd EXIT
This means that REXX will cause TYPE to be run.