Editing Cluster and its component Understanding (section)

=== ⁠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. 

<tt>Mono-spaced Bold</tt> 

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 <tt>my_next_bestselling_novel</tt> in your current working directory, enter the <tt>cat my_next_bestselling_novel</tt> 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 <tt>mono-spaced bold</tt>. For example: 

File-related classes include <tt>filesystem</tt> for file systems, <tt>file</tt> for files, and <tt>dir</tt> 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. 

<tt>''Mono-spaced Bold Italic''</tt> 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 <tt>ssh ''username''@''domain.name''</tt> at a shell prompt. If the remote machine is <tt>example.com</tt> and your username on that machine is john, type <tt>ssh john@example.com</tt>. 

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

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

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.