Conventions used

There are a number of text conventions used throughout this book.

Code in text: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: "When activating a module, the semodule command will copy those modules into a dedicated directory."

A block of code is set as follows:

  chain input {
    type filter hook input priority 0;
    ct state new meta secmark set tcp dport map @secmapping_in
    ct state new ct secmark set meta secmark
    ct state established,related meta secmark set ct secmark
  }

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

(roleattributeset cil_gen_require system_r)
(block pgpool
  (type domain)
  (roletype .system_r domain)
)

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

$ cat /etc/passwd
cat: /etc/passwd: Permission denied

Bold: Indicates a new term, an important word, or words that you see onscreen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: "This can be accomplished through the Open Policy button, or by navigating to File | Open Policy."

Tips or important notes

Appear like this.