Conventions

This book uses the following typographical conventions:

italic

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

constant-width

Is used to show the contents of files, command syntax, and the output from commands.

constant-italic

Is used in examples to show variables for which a context-specific substitution should be made. (The variable filename, for example, would be replaced by some actual filename.)

[ 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 is an example of a Note. Notes are short asides that convey supplemental information that may not be important to all readers.

This is an example of a Warning. Warnings highlight dangerous procedures?those that may damage you, your hardware, or your data. Disregard warnings at your own peril.