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eBooks

Software Development

An Introduction to Core Data and SwiftUI

An Introduction to Core Data and SwiftUI

A common requirement when developing iOS apps is to store data in some form of structured database. One option is to directly manage data using an embedded database system such as SQLite. While this …
A SwiftUI DocumentGroup Tutorial

A SwiftUI DocumentGroup Tutorial

The previous chapter provided an introduction to the DocumentGroup scene type provided with SwiftUI and explored the architecture that makes it possible to add document browsing and management to …
An Overview of SwiftUI DocumentGroup Scenes

An Overview of SwiftUI DocumentGroup Scenes

The chapter entitled “SwiftUI Architecture” introduced the concept of SwiftUI scenes and explained that the SwiftUI framework, in addition to allowing you to build your own scenes, also includes two …
Creating a Customized SwiftUI ProgressView

Creating a Customized SwiftUI ProgressView

The SwiftUI ProgressView, as the name suggests, provides a way to visually indicate the progress of a task within an app. An app might, for example, need to display a progress bar while downloading a …

Operating Systems

Basic Ubuntu 20.04 Firewall Configuration with firewalld

All Linux distributions are provided with a firewall solution of some form. In the case of Ubuntu this takes the form of the Uncomplicated Firewall outlined in the previous chapter. This chapter will …

Using gufw and ufw to Configure an Ubuntu 20.04 Firewall

In the previous chapter we looked at ports and services on an Ubuntu system. We also briefly looked at iptables firewall rules on Ubuntu including the creation of a few very simple rules from the …

Ubuntu 20.04 Firewall Basics

A firewall is a vital component in protecting an individual computer system or network of computers from external attack (typically from an internet connection). Any computer connected directly to an …

Ubuntu 20.04 Network Management

It is difficult to envisage an Ubuntu system that does not have at least one network connection, and harder still to imagine how such an isolated system could be of much practical use. The simple fact …