COMMNDxx is an optional, installation-created list of automatic commands the system internally issues as part of system initialization. COMMNDxx is useful for automatic entry of commands that are frequently issued at system initialization.
You cannot use this member to issue JES commands, because JES is not started when the system issues the COMMNDxx commands.
System trace is activated during the IPL. You can deactivate system trace or change trace options by using the TRACE operator command or by selecting a COMMNDxx parmlib member that contains the options you want. (For information about the TRACE command, see z/OS MVS System Commands.)
Some console-oriented commands affect the operation of a console. You can issue a console-oriented command directly from a console or you can place the command in a COMMNDxx member. If you place a console-oriented command (other than CONTROL M) in COMMNDxx and you do not specify a routing location operand, the system does not execute the command and might not generate an error message. The CONTROL M command does not support routing location operands, but it is valid in COMMNDxx.
When you specify the routing location operands, do so only as described in z/OS MVS System Commands.
If you do not include CMD=xx in the system parameter list (IEASYSxx), or if the operator does not specify CMD=xx, the system searches for the COMMND00 member by default. The COMMND00 member, if it exists, is read if CMD=xx is not included in the system parameter list (IEASYSxx) or is not specified by the operator. If the system cannot locate either the specified COMMNDxx member or COMMND00 during initialization, processing continues without automatic commands.