Reading syntax diagrams

Command names

The command name can consist of a single action word, such as HALT, or it can consist of an action word and an object for the action, such as DEFINE DOMAIN. You can enter the command in any column of the input line.

Enter the entire command name or the abbreviation that is specified in the syntax diagram for the command. Uppercase letters denote the shortest acceptable abbreviation. If a command appears entirely in uppercase letters, you cannot abbreviate it. You can enter the command in uppercase letters, lowercase letters, or any combination. In this example, you can enter CMDNA, CMDNAM, or CMDNAME in any combination of uppercase and lowercase letters.

Required parameters

When a parameter is on the same line as the command name, the parameter is required. When two or more parameter values are in a stack and one of them is on the line, you must specify one value.

In this example, you must enter PARMNAME=A, PARMNAME=B, or PARMNAME=C. Do not include any blanks immediately before or after the equal sign (=).

Optional parameters

When a parameter is below the line, the parameter is optional. In this example, you can enter PARMNAME=A or nothing at all. Do not include any blanks immediately before or after the equal sign (=).

When two or more parameter values are in a stack below the line, all of them are optional. In this example, you can enter PARMNAME=A, PARMNAME=B, PARMNAME=C, or nothing at all. Do not include any blanks immediately before or after the equal sign (=).

Defaults

Defaults are above the line. The system uses the default unless you override it. You can override the default by entering an option from the stack below the line.

In this example, PARMNAME=A is the default. You can also enter PARMNAME=A, PARMNAME=B, or PARMNAME=C. Do not include any blanks before or after the equal sign (=).

Variables

Highlighted lowercase items (like this) denote variables. In these examples, var_name represents variables::

Special characters

You must code these symbols exactly as they appear in the syntax diagram.

*

Asterisk

:

Colon

,

Comma

=

Equal sign

-

Hyphen

( )

Parentheses

.

Period

Repeating values

An arrow returning to the left means that the item can be repeated. A character within the arrow means that you must separate repeated items with that character.

Repeatable choices

A stack of values followed by an arrow returning to the left means that you can select more than one value or, when permitted, repeat a single item. In this example, you can choose more than one value, with each name delimited with a comma. Do not include any blanks before or after the equal sign (=).

Footnotes

Footnotes are enclosed in parentheses.

Notes:

• ¹ You can specify up to five file names.

Entering parameters

The order in which you enter parameters can be important. The following example shows a portion of the command for defining a copy storage pool:

The first two parameters in this command (pool_name and device_class_name are required parameters. pool_name and device_class_name are also positional. That is, they must be entered in the order shown, immediately after the command name. The POOLTYPE parameter is a required keyword parameter. DESCRIPTION and RECLAIM, are optional keyword parameters. Keyword parameters are identified by an equal sign that specifies a specific value or a variable. Keyword parameters must follow any positional parameters in a command.

The following command entries, in which the keyword parameters are ordered differently, are both acceptable:

define stgpool mycopypool mydeviceclass pooltype=copy description=engineering
   reclaim=50
define stgpool mycopypool mydeviceclass description=engineering pooltype=copy
   reclaim=50

The following example, in which one of the positional parameters follows a keyword parameter, is not acceptable:

define stgpool mycopypool pooltype=copy mydeviceclass description=engineering  
   reclaim=50

Syntax fragments

Some diagrams, because of their length, must display parts of the syntax with fragments. The fragment name appears between vertical bars in the diagram.

The expanded fragment appears in the diagram after all other parameters or at the bottom of the diagram. A heading with the fragment name identifies the expanded fragment. Commands appearing directly on the line are required.

In this example, the fragment is named Fragment.

Fragment