What Typographic Changes and Symbols Mean

Command names, C code, UNIX code, system calls, header files, data structures, declarations, short examples, file names, and path names are printed in listing (constant width) font.

User input is in listing font when by itself, or bold listing font when used in combination with computer output.

Items being emphasized, variable names, and parameters are printed in italics.

Screens are used to simulate what a user will see on a
video display screen or to show program source code.

Data structure contents and formats are also shown in screens.

The Note sign is used to emphasize points of interest, to present parenthetical information, and to cite references to other documents and commands.