[ ]

Contains optional arguments and command options. 

ls [-l]

The -l option is not required.

{ | }

Contains a set of choices for a required command option. 

-d {y|n}

The -d option requires that you use either the y argument or the n argument.

${ }

Indicates a variable reference. 

${com.sun.javaRoot}

References the value of the com.sun.javaRoot variable.

- 

Joins simultaneous multiple keystrokes. 

Control-A 

Press the Control key while you press the A key. 

+ 

Joins consecutive multiple keystrokes. 

Ctrl+A+N 

Press the Control key, release it, and then press the subsequent keys. 

-> 

Indicates menu item selection in a graphical user interface. 

File -> New -> Templates 

From the File menu, choose New. From the New submenu, choose Templates.