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 are shown as follows: "The development packages always have the -dev suffix in their package name—in this case, it would be the libssl-dev package".

A block of code is set as follows:

define host
{
  host_name     somemachine
  address       10.0.0.1
  check_command check-host-alive
}

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

define host
{
  host_name     somemachine
  address       10.0.0.1
 _MAC 12:12:12:12:12:12
  check_command check-host-by-mac
}

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

/opt/nagios/plugins/check_ping -H 10.0.0.1 -w 3000.0,80% -c 5000.0,100% -p 5

New terms and important words are introduced in a bold-type font. Words that you see on the screen, in menus or dialog boxes for example, appear in our text like this: "It can be accessed by clicking on the Tactical Overview link in the left-side menu".