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Structure of JCL Statements

JCL Statement Structure:

  • JCL statements are coded in 80 bytes.

  • 72 of the 80 columns are available to code JCL.

  • Last 8 columns are reserved for an optional sequence number.

  • Each JCL statement is divided into several fields.

Syntax or Format:

jcl statement structure

Let's us see each field in detail,

1. Identifier Field:

  • The identifier field identifies a record as a JCL statement.

  • For most JCL statements, the identifier field occupies the first two character positions and must contain two slashes (//). There are two exceptions.

  • First, the delimiter statement has a slash in column 1 and an asterisk in column 2 (/*).

  • Second, the identifier field for a comment statement is three characters long: The first two columns contain slashes and the third contains an asterisk (//*).


jcl identifier field

2. Name Field:

It follows identifier field. The name field associates a name with a JCL statement.
  • It is not mandatory everywhere; but it is always required on a JOB statement, where it supplies a name for a job.

  • A name field must begin in column 3, right after the identifier field.

  • It consists of one to eight characters, which may be letters, numbers or national characters (#, @, and $) Also, the first character of a name should be a letter or a national character.


jcl name field

Name field - Incorrect values:

Here the Name field is of length 9 characters hence we get this error:

jcl invalid name field example 1

Note here the Name field begins with a numeric value. Hence we get this error.

jcl invalid name field example 2

3. Operation Field:

The operation field follows the name field and it specifies the statements function.
  • JOB, EXEC, and DD are the different operation fields.

  • This field can be coded anywhere in the JCL, but it should be separated from the name field by at least one blank.

  • However, conventionally, the operation field should be started in column 12.


jcl operation field

4. Parameters Field:

The parameters field begins at least one position after the end of the operation field and can extend into column 71:
  1. Within the parameters field, we have to code one or more parameters that supply information that influences how the statement is processed.

  2. When a parameters field consists of more than one parameter, the individual parameters should be separated with commas.

  3. MVS assumes that the parameters field is complete when it encounters a space so do not include a space by accident. If you need to include a space as part of a parameter value, the parameter value must be enclosed in apostrophes.


jcl parameters field

There are two types of parameters:

  1. Positional
  2. Keyword
We will be discussing about each parameters in next chapter.

5. Comments Field:

Following the parameters field, you can code brief comments in the comments field.
  • The comments field begins in the position after the space that marks the end of the parameters field and ends in column 71.

  • MVS ignores what is coded here, so you can record any comments you wish.

  • You can also use an entire line as a comment.

  • For this, you need to code //* starting from column one of the JCL record.


jcl comments field

How to continue JCL statements?

When it is not possible to fit all the parameters on a single 80-character line, the statement can be continued onto one or more additional lines by following the below steps:
  • Break the parameter field after the comma that follows a parameter or sub-parameter.

  • Code slashes in columns 1 and 2 of the following line.

  • Code the next parameter beginning anywhere in columns 4 through 16.


jcl continue statement example

Video Tutorial: JCL Statement Structure

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