Conventions

In this book, you will find a number of styles of text 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: "You can concatenate arrays with the + operator or append them with the << operator."

A block of code is set as follows:

slice ($firewall_rules,2) |$ip, $port| {firewall {"$port from $ip": dport  => $port, source => "$ip", action => 'accept', }
}

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

Notice: 1
Notice: 2
Notice: 3
Notice: 4
Notice: 5
# 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, in menus or dialog boxes for example, appear in the text like this: "In this graph it is easy to see that Package['ntp'] is the first resource to apply, then File['/etc/ntp.conf'] and finally Service['ntp']."