Conventions

In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "For example, background-color will throw an error, so you should write 'background-color'."

A block of code is set as follows:

var cart = ko.observableArray([]);
var showCartDetails = function () {
  if (cart().length > 0) {
    $("#cartContainer").removeClass("hidden");
  }
};
[default]
exten => s,1,Dial(Zap/1|30)
exten => s,2,Voicemail(u100)
exten => s,102,Voicemail(b100)
exten => i,1,Voicemail(s0)

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

[default]
exten => s,1,Dial(Zap/1|30)
exten => s,2,Voicemail(u100)
exten => s,102,Voicemail(b100)
exten => i,1,Voicemail(s0)
<button class="btn btn-primary btn-sm" data-bind="click: showCartDetails, enable: cart().length > 0">
  Show Cart Details
</button>

<button class="btn btn-primary btn-sm" data-bind="click: showCartDetails, disable: cart().length < 1">
  Show Cart Details
</button>

Any command-line input or output is written as follows:

# cp /usr/src/asterisk-addons/configs/cdr_mysql.conf.sample
 /etc/asterisk/cdr_mysql.conf

New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: "Once we have clicked on the Confirm Order button, the order should be shown to us to review and confirm if we agree."