The conventions used to present command syntax in this book are the same conventions used in the IOS Command Reference. The Command Reference describes these conventions as follows :
Vertical bars () separate alternative, mutually exclusive elements.
Square brackets [ ] indicate optional elements.
Braces { } indicate a required choice.
Braces within brackets [{ }] indicate a required choice within an optional element.
Boldface indicates commands and keywords that are entered literally as shown. In actual configuration examples and output (not general command syntax), boldface indicates commands that are manually input by the user (such as a show command).
Italics indicates arguments for which you supply actual values.