Conventions Used in This Handbook (sed & awk, Second Edition)

0.4. Conventions Used in This Handbook

The following conventions are used in this book:

Bold: is used for statements and functions, identifiers, and program names.
Italic: is used for file and directory names when they appear in the body of a paragraph as well as for data types and to emphasize new terms and concepts when they are introduced.
Constant Width: is used in examples to show the contents of files or the output from commands.
Constant Bold: is used in examples to show command lines and options that should be typed literally by the user. (For example, rm foo means to type "rm foo" exactly as it appears in the text or the example.)
"": are used to identify a code fragment in explanatory text. System messages and symbols are quoted as well.
$: is the UNIX Bourne shell or Korn shell prompt.
[]: surrounds optional elements in a description of program syntax. (The brackets themselves should never be typed, unless otherwise noted.)
...: stands for text (usually computer output) that's been omitted for clarity or to save space.
: indicates a literal space. This symbol is used to make spaces visible in examples, as well as in the text.
•: indicates a literal TAB character. This symbol is used to make tabs visible in examples, as well as in the text.

The notation CTRL-X or ^X indicates use of control characters. It means hold down the "control" key while typing the character "x". We denote other keys similarly (e.g., RETURN indicates a carriage return). All examples of command lines are followed by a RETURN unless otherwise indicated.