Typographic Conventions

This document uses the following typographical conventions:

%, $, or #: A percent sign represents the C shell system prompt. A dollar sign represents the system prompt for the Bourne, Korn, and POSIX shells. A number sign represents the superuser prompt.
audit(5): A manpage. The manpage name is audit, and it is located in Section 5.
Command: A command name or qualified command phrase.
Computer output: Text displayed by the computer.
Ctrl+x: A key sequence. A sequence such as Ctrl+x indicates that you must hold down the key labeled Ctrl while you press another key or mouse button.
Document Title: The title of a document. On the web and on the Instant Information media, it may be a hot link to the document itself.
ENVIRONMENT VARIABLE: The name of an environment variable, for example, PATH.
ERROR NAME: The name of an error, usually returned in the errno variable.
Key: The name of a keyboard key. Return and Enter both refer to the same key.
Term: The defined use of an important word or phrase.
User input: Commands and other text that you type.
Variable: The name of a placeholder in a command, function, or other syntax display that you replace with an actual value.
[]: The contents are optional in syntax. If the contents are a list separated by |, you must choose one of the items.
{}: The contents are required in syntax. If the contents are a list separated by |, you must choose one of the items.
...: The preceding element can be repeated an arbitrary number of times.
⋮: Indicates the continuation of a code example.
|: Separates items in a list of choices.
WARNING: A warning calls attention to important information that if not understood or followed will result in personal injury or nonrecoverable system problems.
CAUTION: A caution calls attention to important information that if not understood or followed will result in data loss, data corruption, or damage to hardware or software.
IMPORTANT: This alert provides essential information to explain a concept or to complete a task.
NOTE: A note contains additional information to emphasize or supplement important points of the main text.

Examples and Shells

This document describes practices used by the system administrator. Since the root user (superuser) is required to use the POSIX shell /sbin/sh, all command examples use that shell. The POSIX shell is defined in sh-posix(1). For information on other shells, see the Shells User’s Guide and sh(1).

Command Syntax

Literal: A word or character that you enter literally.
Replaceable: A word or phrase that you replace with an appropriate value.
-chars: One or more grouped command options, such as -ikx. The chars are usually a string of literal characters that each represent a specific option. For example, the entry -ikx is equivalent to the individual options -i, -k, and -x. The plus character (+) is sometimes used as an option prefix.
-word: A single command option, such as -help. The word is a literal keyword. The difference from -chars is usually obvious and is clarified in an Options description. The plus character (+) and the double hyphen (--) are sometimes used as option prefixes.
[ ]: The bracket metacharacters enclose optional content in formats and command descriptions.
{ }: The brace metacharacters enclose required content in formats and command descriptions.
|: The bar metacharacter separates alternatives in a list of choices, usually in brackets or braces.
. . .: The ellipsis metacharacter after a token (abc...) or a right bracket ([ ]...) or a right brace ({ }...) metacharacter indicates that the preceding element and its preceding whitespace, if any, may be repeated an arbitrary number of times.
. . .: Ellipsis is sometimes used to indicate omitted items in a range.

Typographic Conventions

Technical documentation

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Examples and Shells

Command Syntax