# Conventions Used in This Book

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.
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. For example, it is used with line numbers in the descriptions of files and programs.
`Teletype`
  (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 teletype font.
`Teletype Bold`
  is used in examples to show commands or text that would be typed in literally by the user.
`Teletype Italic`
`Teletype 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.) Constant italic is also used to highlight line numbers in examples (like `12>`). These line numbers are not part of the file; they are for reference only.
function(n)
  is a reference to a manual page in Section n of the UNIX programmer's manual. For example, mh-format(5) refers to a page called mh-format in Section 5.
`%`
  is the C shell prompt.
`$`
  is the Bourne shell prompt.
`...`
  stands for text (usually computer output) that's been omitted for clarity or to save space.
`:-)`
  is an "electronic smiley face," a convention in electronic communication. It means "don't take that seriously."
`CTRL`
  stands for 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. Control characters are also shown with a caret (`^`) and the letter, as in `^D`.
`META`
  stands for a Meta character. Meta characters are written as follows: if the character is a lowercase letter, the meta character will appear as META-C. If the character is an uppercase letter, the meta character will appear as META-SHIFT-C. To create META-C, for example, hold down the "Meta" key and press the "c" key. To make the META-SHIFT-C character, hold down both the "Meta" key and the SHIFT (shift) key and press the "c" key. The Meta key isn't always labeled "Meta". If your keyboard doesn't have Meta keys, try using a utility like xmodmap(1) to redefine some other key -- or use another command to do what you need.