[ ] 

Encloses optional arguments and command options 

ls [-l]

The -l option is optional.

{ | } 

Encloses 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 variable com.sun.javaRoot.

- 

Joins simultaneous multiple keystrokes 

Ctrl-A 

Hold down the Control key while pressing the A key.  

+ 

Joins consecutive multiple keystrokes 

Ctrl+A+N 

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

-> 

Indicates hierarchical menu selection in a graphical user interface 

File -> New -> Templates 

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