You can use a set of z/OS UNIX extensions to TSO/E REXX—host commands and functions—to access kernel callable services. The z/OS UNIX extensions, called syscall commands, have names that correspond to the names of the callable services that they invoke—for example, access, chmod, and chown.

You can run a REXX program with z/OS UNIX extensions from MVS™, TSO/E, the shell, or a C program. The exec is not portable to an operating system that does not have z/OS UNIX installed.

For more information about the REXX extensions that call z/OS UNIX services, see z/OS Using REXX and z/OS UNIX System Services.