This book uses the following typographical conventions:
Italic
Indicates the names of files, databases, directories, hostnames, domain names, usernames, sendmail feature names , Unix utilities, programs, and it is used to emphasize new terms when they are first introduced.
Constant width
Indicates sendmail.cf literals, commands and variables , m4 macros and built-in commands, and Unix command-line options. It is used to show the contents of files and the output from commands. Keywords are also in constant width .
Constant width bold
Used in examples to show commands or text that you would type.
Constant width italic
Used in examples and text to show variables for which a context-specific substitution should be made. (The variable filename , for example, would be replaced by some actual filename.)
$ , #
When we demonstrate commands that you would give interactively, we normally use the default Bourne shell prompt ( $ ). If the command must be executed as root , then we use the default superuser prompt ( # ).
[ option ]
When showing command syntax, we place optional parts of the command within brackets. For example, ls [ -l ] means that the -l option is not required.
This icon signifies a tip, suggestion, or general note.
