# Preface

## 1. Document Conventions

This manual uses several conventions to highlight certain words and phrases and draw attention to specific pieces of information.

### 1.1. Typographic Conventions

Four typographic conventions are used to call attention to specific words and phrases. These conventions, and the circumstances they apply to, are as follows.

`Mono-spaced Bold`

Used to highlight system input, including shell commands, file names and paths. Also used to highlight keys and key combinations. For example:

> To see the contents of the file `my_next_bestselling_novel` in your current working directory, enter the cat my_next_bestselling_novel command at the shell prompt and press Enter to execute the command.

The above includes a file name, a shell command and a key, all presented in mono-spaced bold and all distinguishable thanks to context.

Key combinations can be distinguished from an individual key by the plus sign that connects each part of a key combination. For example:

> Press Enter to execute the command.

> Press Ctrl+Alt+F2 to switch to a virtual terminal.

The first example highlights a particular key to press. The second example highlights a key combination: a set of three keys pressed simultaneously.

If source code is discussed, class names, methods, functions, variable names and returned values mentioned within a paragraph will be presented as above, in `mono-spaced bold`. For example:

> File-related classes include `filesystem` for file systems, `file` for files, and `dir` for directories. Each class has its own associated set of permissions.

Proportional Bold

This denotes words or phrases encountered on a system, including application names; dialog-box text; labeled buttons; check-box and radio-button labels; menu titles and submenu titles. For example:

> Choose System → Preferences → Mouse from the main menu bar to launch Mouse Preferences. In the Buttons tab, select the Left-handed mouse check box and click Close to switch the primary mouse button from the left to the right (making the mouse suitable for use in the left hand).

> To insert a special character into a gedit file, choose Applications → Accessories → Character Map from the main menu bar. Next, choose Search → Find… from the Character Map menu bar, type the name of the character in the Search field and click Next. The character you sought will be highlighted in the Character Table. Double-click this highlighted character to place it in the Text to copy field and then click the Copy button. Now switch back to your document and choose Edit → Paste from the gedit menu bar.

The above text includes application names; system-wide menu names and items; application-specific menu names; and buttons and text found within a GUI interface, all presented in proportional bold and all distinguishable by context.

Mono-spaced Bold Italic or Proportional Bold Italic

Whether mono-spaced bold or proportional bold, the addition of italics indicates replaceable or variable text. Italics denotes text you do not input literally or displayed text that changes depending on circumstance. For example:

> To connect to a remote machine using ssh, type ssh username@domain.name at a shell prompt. If the remote machine is `example.com` and your username on that machine is john, type ssh john@example.com.

> The mount -o remount file-system command remounts the named file system. For example, to remount the `/home` file system, the command is mount -o remount /home.

> To see the version of a currently installed package, use the rpm -q package command. It will return a result as follows: package-version-release.

Note the words in bold italics above — username, domain.name, file-system, package, version and release. Each word is a placeholder, either for text you enter when issuing a command or for text displayed by the system.

Aside from standard usage for presenting the title of a work, italics denotes the first use of a new and important term. For example:

> Publican is a DocBook publishing system.

### 1.2. Pull-quote Conventions

Terminal output and source code listings are set off visually from the surrounding text.

Output sent to a terminal is set in `mono-spaced roman` and presented thus:

    books        Desktop   documentation  drafts  mss    photos   stuff  svn
    books_tests  Desktop1  downloads      images  notes  scripts  svgs

Source-code listings are also set in `mono-spaced roman` but add syntax highlighting as follows:

    package org.jboss.book.jca.ex1;

    import javax.naming.InitialContext;

    public class ExClient
    {
       public static void main(String args[])
           throws Exception
       {
          InitialContext iniCtx = new InitialContext();
          Object         ref    = iniCtx.lookup("EchoBean");
          EchoHome       home   = (EchoHome) ref;
          Echo           echo   = home.create();

          System.out.println("Created Echo");

          System.out.println("Echo.echo('Hello') = " + echo.echo("Hello"));
       }
    }

### 1.3. Admonitions

Finally, we use three visual styles to draw attention to information that might otherwise be overlooked.

Note

Notes are tips, shortcuts or alternative approaches to the task at hand. Ignoring a note should have no negative consequences, but you might miss out on a trick that makes your life easier.

Tip

Tips are tips, shortcuts or alternative approaches to the task at hand. Ignoring a tip should have no negative consequences, but you might miss out on a trick that makes your life easier.

Important

Important boxes detail things that are easily missed: configuration changes that only apply to the current session, or services that need restarting before an update will apply. Ignoring a box labeled “Important” will not cause data loss but may cause irritation and frustration.

Caution

Warnings should not be ignored. Ignoring warnings will most likely cause data loss.

Warning

Warnings should not be ignored. Ignoring warnings will most likely cause data loss.