Conventions

This book uses the following typographical conventions:

Italic

is used for the names of files, directories, hostnames, domain names, and to emphasize new terms when they are first introduced.

Bold

is used for command names.

Constant width

is used to show the contents of files or the output from commands. Keywords are also in constant width .

Constant bold

is used in examples to show commands or text that you would type.

Constant italic

is 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 C shell prompt ( % ). If the command must be executed as root, then we use the default superuser prompt ( # ). Because the examples may include multiple systems on a network, the prompt may be preceded by the name of the system on which the command was given.

[  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.