Using JCL statement keywords and symbols to override JCL

You can use JCL statement keywords and symbols to override existing JCL.

With the exception of the keywords listed in Note 2 below, JOB statement keyword parameters include those keywords that are defined for the MVS JCL JOB statement. Such keywords add to or override the specification of the JOB statement keywords. EXEC statement keyword parameters include those keywords that are defined for the MVS JCL EXEC statement. The treatment of these keywords depends on whether the target of the START command is a job or a procedure; see the following table for more information. EXEC keywords that are also JOB keywords, such as TIME and REGION, are treated as JOB keywords.

JOB statement keyword parameters are those keywords defined for the MVS™ JCL JOB statement. These keywords will add to or override the specification of the JOB statement keywords. The EXEC statement keyword parameters are those keywords defined for the MVS JCL EXEC statement. The treatment of these keywords depends on whether the target of the START command is a job or a procedure. See the following table. EXEC keywords that are also JOB keywords, such as TIME and REGION, are treated as JOB keywords.

In this next example, assume ABC is a procedure, not a job. The following START command creates a REGION=200K parameter on the JOB statement and a DYNAMNBR=2 parameter on the EXEC statement:

  START  ABC.DEF,REGION=200K,DYNAMNBR=2

The result of the command is the following JCL:

//ABC     JOB REGION=200K,MSGLEVEL=1
//DEF     EXEC ABC,DYNAMNBR=2

You can use symbols to override other symbols that are specified in the procedure to be started. For example, the following command starts customer information control system (CICS®) with a 20K region:

START  CICS,A=20K

A=20K overrides A=10K on the following PROC statement:

//CICS  PROC  A=10K
//      EXEC  PGM=XYZ,REGION=&A

The command results in the following JCL:

//CICS     JOB MSGLEVEL=1
//STARTING EXEC  CICS,A=20K

Note: Select names for symbols carefully; see Coding symbols in JCL for rules to use when coding and naming symbols.

The following table describes the actions that result from specifying various keywords and symbols on the START command:

Source JCL	Keyword	Result
JOB	JOB (see Note 2)	Overrides or added to source JOB statement
JOB	EXEC	Placed on SET statement as a symbol
JOB	DD	Overrides, or added to, source IEFRDER DD statement
Procedure	Other (see Note 1)	Placed on SET statement as a symbol
Procedure	JOB	Overrides, or added to, source JOB statement
Procedure	EXEC	Placed on EXEC memname statement overriding keyword
Procedure	DD	Overrides, or added to, source IEFRDER DD statement
JOB	Other (see Note 1)	Placed on EXEC memname statement as symbol

Notes:

Note 1: Other does not include the START command reserved words SUB, JOBNAME, and JOBACCT.
Note 2: The following keywords are not merged into the JOB statement, which allows their use as symbol names on the START command:
- SYSAFF
- SYSTEM