Conventions Used in This Handbook
The following typographic conventions are used in this book:
- Italic
Used for names, including pathnames, filenames, program and command names, usernames, hostnames, machine names, and mailing-list names, as well as for mail addresses. Italics are also used to indicate that part of a program’s output is not specific. For example, "
error: number or file" indicates that the error will be shown either as a number or as a filename. In addition, italics are used to emphasize new terms and concepts when they are introduced.-
Constant Width Used in examples to show the contents of files or the output from commands. This includes examples from the configuration file, or other files, such as message files, shell scripts, or C-language program source. Constant-width text is quoted only when it is necessary to show enclosed space; such as, the five-character "
From" header.Single characters, symbolic expressions, and command-line switches are always shown in constant-width font. For instance, the
ooption illustrates a single character, the rule$-illustrates a symbolic expression, and-dillustrates a command-line switch.-
Constant Width Italic Used in examples and text 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 Bold Used in examples to show commands or other text that is to be typed literally by the user. For example, the phrase
cat/var/run/sendmail.pid ...