Understanding the syntax diagrams
A syntax diagram uses symbols to represent the elements of a command and to specify the rules for using these elements.
Syntax diagrams
- Main path line
-
Begins on the left with double arrowheads (>>) and ends on the right with two arrowheads facing each other (><). If a diagram is longer than one line, each line to be continued ends with a single arrowhead (>) and the next line begins with a single arrowhead. Read the diagrams from left-to-right, top-to-bottom, following the main path line.
- Keyword
-
Represents the name of a command, parameter, or argument. A keyword is not in italics. Spell a keyword exactly as it is shown in the syntax diagram.
- Required keywords
-
Indicates the parameters or arguments you must specify for the command. Required keywords appear on the main path line. Mutually exclusive required keywords are stacked vertically.
- Optional keywords
-
Indicates the parameters or arguments you can choose to specify for the command. Optional keywords appear below the main path line. Mutually exclusive optional keywords are stacked vertically.
- Variable
-
Represents the value you need to supply for a parameter or argument, such as a file name, user name, or password. Variables are in italics.
Special characters
- - (minus) or / (slash) sign
- Parameters are prefixed with a - (minus) sign. Parameters define the action of a command or modify the operation of a command. You can use multiple parameters, followed by variables, when you issue a command.
- [ ] square brackets
- Optional values are enclosed in square brackets.
- { } braces
- Required or expected values are enclosed in braces.
- | vertical bar
- A vertical bar indicates that you have a choice between
two or more options or arguments.
For example, [ a | b ] indicates that you can choose a, b, or nothing. Similarly, { a | b } indicates that you must choose either a or b.
- ... ellipsis
- An ellipsis signifies the values that can be repeated on the command line or multiple values or arguments.
- - dash
- A dash indicates that, as an alternative to entering the parameter, a value or values are supplied from stdin. stdin varies depending on your settings and is available when you are using single-shot or script mode. This option is not available when using interactive mode.