According to the developers of Tails: NSA (National Security Agency) has taken a number of approaches to put pressure on many free software projects and their developers. And, during a LinuxCon technology conference, the founder of Linux, Linus Torvalds revealed that the NSA hoped to install a backdoor in his operating system. In other words, for even Linux distributions, they are not absolutely safe now.

The kernel of Linux is responsible for handling all the interactions between CPU and outside world, deciding the order of all programs share the processor time, effectively managing hundreds or thousands of processes to share the limited memory available in system, skillfully planning the data transmission as a whole to save the time consumed by CPU on waiting for the slower hard drive. Therefore, in-depth study of the most essential parts of the Linux kernel lets you completely understand what makes Linux run normally and why it can work well in various system distributions.

CentOS (short for Community ENTerprise Operating System) is a free, open-source, enterprise-class and community-supported computing platform that derived from the same source code with Red Hat Enterprise Linux OS. At present, there have been increasing Internet services or applications around the world that require high stability (including a variety of purposes of servers and business applications) are running on it, rather than RHEL.

After all, Google is the first company attempted the localization of Android on PC. Whereas, they missed the era of mobile Internet & network and smartphone sweeping around the world due to an early start. Subsequent years, Android-x86 appeared first and lay a solid foundation for newcomers to make transition. Then it's Phoenix OS and Remix OS's turn to break a new ground. AppNee thinks that: the day Android rooted on a PC platform (that means compatibility is no longer a major problem), the time Linux started to formally replace Windows in all directions!

Linux beginners probably encounter problems like this: feel confused and puzzled facing multifarious tutorial books. Considering the quality level of books and the limited energy of individual, we all hope to be able to pick out the best ones. While, most often, we just got the opposite of what we want, or got half the results with twice the effort. Fortunately, The Linux Command Line (TLCL for short) came out. By reading it, we can go less detours and master more key knowledge.