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| Preface |

## Typefaces and Other Conventions

Italic

  is used for the names of all UNIX utilities, switches, directories, and filenames and to emphasize new terms and concepts when they are first introduced. It's also used in programs and examples to explain what's happening or what's been left out at the `...` marks.

Bold

  is used occasionally within text to make words easy to find-just like movie stars' names in the People section of your local newspaper.

`Constant`

`Width`

  is used for sample code fragments and examples. A reference in text to a word or item used in an example or code fragment is also shown in constant width font.

`Constant`

`Bold`

  is used in examples to show commands or text that would be typed in literally by the user.

`Constant`

`Italic`,

`Bold`

`Italic`

  are used in code fragments and 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.)

function(n)

  is a reference to a manual page in Section n of the UNIX programmer's manual. For example, getopt(3) refers to a page called getopt in Section 3.

`%`

  is the C shell prompt.

`$`

  is the Bourne shell prompt.

`:-)`

  is a "smiley face" that means "don't take this seriously." The idea started on Usenet (1.33) and it spread (51.12).

&`...`

  stands for text (usually computer output) that's been omitted for clarity or to save space.

CTRL

  starts a control character. To create CTRL-d, for example, hold down the "control" key and press the "d" key. Control characters are not case sensitive; "d" refers to both the uppercase and lowercase letter. The notation `^D` also means CTRL-d. Also, you'll sometimes see the key sequence in a box (for example, `[CTRL-d]` when we want to make it clear exactly what you should type.

  is used in some examples to represent a space character.

`TAB`

  is used in some examples to represent a TAB character.

What's New in the Second Edition |  | The Authors