Conventions Used in This Book

The following is a list of the typographical conventions used in this book:


Used to indicate new terms, URLs, filenames, file extensions, directories, commands and options, and program names, and to highlight comments in examples. For example, a path in the filesystem will appear as /Developer/Applications.

Constant width

Used to show code examples, the contents of files, or the output from commands.

Constant width bold

Used for emphasis and user input in code.

Constant width italic

Used in examples and tables to show text that should be replaced with user-supplied values.


The second color is used to indicate a cross reference within the text.


[RETURN] (in square brackets, bold and all-caps) at the end of a line of code is used to denote an unnatural line break; that is, you should not enter these as two lines of code, but as one continuous line. Multiple lines are used in these cases due to page-width constraints.

You should pay special attention to notes set apart from the text with the following icons:

This is a tip, suggestion, or general note. It contains useful supplementary information about the topic at hand.

This is a warning or note of caution.

The thermometer icons, found next to each hack, indicate the relative complexity of the hack:

figs/beginner.gif beginner
figs/moderate.gif moderate
figs/expert.gif expert