The calculation is a little tricky, but mostly because we have to accommodate leap years. Since the start of the epoch, we've had 12 leap years, starting in 1972, the last in 2016. Conversely, you ...could use the seconds per year figures presented earlier and just do this: $ expr 31536000 \* 38 + 31622400 \* 12 1577836800 This way of tracking dates and times made Unix systems fairly impervious to the Y2K scare that had people in late 1999 worried that moving into the year 2000 would wreak havoc on computer systems. ...only applications which stored years in a two-digit format would see the year going to 00 as a sign that time jumping backwards.
Create simple to advanced shell scripts and enhance your system functionality with effective recipesKey FeaturesAutomate tedious and repetitive tasksCreate several novel applications ranging from a ...simple IRC logger to a Web ScraperManage your system efficiently by becoming a seasoned Bash userBook DescriptionIn Linux, one of the most commonly used and most powerful tools is the Bash shell. With its collection of engaging recipes, Bash Cookbook takes you through a series of exercises designed to teach you how to effectively use the Bash shell in order to create and execute your own scripts.
The book starts by introducing you to the basics of using the Bash shell, also teaching you the fundamentals of generating any input from a command. With the help of a number of exercises, you will get to grips with the automation of daily tasks for sysadmins and power users. Once you have a hands-on understanding of the subject, you will move on to exploring more advanced projects that can solve real-world problems comprehensively on a Linux system. In addition to this, you will discover projects such as creating an application with a menu, beginning scripts on startup, parsing and displaying human-readable information, and executing remote commands with authentication using self-generated Secure Shell (SSH) keys.
By the end of this book, you will have gained significant experience of solving real-world problems, from automating routine tasks to managing your systems and creating your own scripts.What you will learnUnderstand the basics of Bash shell scripting on a Linux systemGain working knowledge of how redirections and pipes interactRetrieve and parse input or output of any commandAutomate tasks such as data collection and creating and applying a patchCreate a script that acts like a program with different featuresCustomize your Bash shell and discover neat tricks to extend your programsCompile and install shell and log commands on your system's console using SyslogWho this book is forThe Bash Cookbook is for you if you are a power user or system administrator involved in writing Bash scripts in order to automate tasks. This book is also ideal if you are interested in learning how to automate complex daily tasks.
Leverage Azure's cloud capabilities to find the most optimized path to meet your firm's cloud infrastructure needsKey FeaturesGet to grips with the core Azure infrastructure technologies and ...solutionsDevelop the ability to opt for cloud design and architecture that best fits your organizationCover the entire spectrum of cloud migration from planning to implementation and best practicesBook DescriptionMicrosoft Azure is a powerful cloud computing platform that offers a multitude of services and capabilities for organizations of any size moving to a cloud strategy.This fourth edition comes with the latest updates on cloud security fundamentals, hybrid cloud, cloud migration, Microsoft Azure Active Directory, and Windows Virtual Desktop. It encapsulates the entire spectrum of measures involved in Azure deployment that includes understanding Azure fundamentals, choosing a suitable cloud architecture, building on design principles, becoming familiar with Azure DevOps, and learning best practices for optimization and management.The book begins by introducing you to the Azure cloud platform and demonstrating the substantial scope of digital transformation and innovation that can be achieved with Azure's capabilities. The guide also acquaints you with practical insights into application modernization, Azure Infrastructure as a Service (IaaS) deployment, infrastructure management, key application architectures, best practices of Azure DevOps, and Azure automation.By the end of this book, you will have acquired the skills required to drive Azure operations from the planning and cloud migration stage to cost management and troubleshooting.What you will learnUnderstand core Azure infrastructure technologies and solutionsCarry out detailed planning for migrating applications to the cloud with AzureDeploy and run Azure infrastructure servicesDefine roles and responsibilities in DevOpsGet a firm grip on Azure security fundamentalsCarry out cost optimization in AzureWho this book is forThis book is designed to benefit Azure architects, cloud solution architects, Azure developers, Azure administrators, and anyone who wants to develop expertise in operating and administering the Azure cloud. Basic familiarity with operating systems and databases will help you grasp the concepts covered in this book.
The genomes of cancer cells constantly change during pathogenesis. This evolutionary process can lead to the emergence of drug-resistant mutations in subclonal populations, which can hinder ...therapeutic intervention in patients. Data derived from massively parallel sequencing can be used to infer these subclonal populations using tumor-specific point mutations. The accurate determination of copy-number changes and tumor impurity is necessary to reliably infer subclonal populations by mutational clustering. This protocol describes how to use Sclust, a copy-number analysis method with a recently developed mutational clustering approach. In a series of simulations and comparisons with alternative methods, we have previously shown that Sclust accurately determines copy-number states and subclonal populations. Performance tests show that the method is computationally efficient, with copy-number analysis and mutational clustering taking <10 min. Sclust is designed such that even non-experts in computational biology or bioinformatics with basic knowledge of the Linux/Unix command-line syntax should be able to carry out analyses of subclonal populations.
C++ is a general-purpose programming language with a bias towards systems programming. This book provides a detailed walkthrough of the C, C++ and POSIX standards and enables a firm understanding of ...various system calls for UNIX systems. Topics include console and file IO, memory management, sockets, time interface, process and thread management.
Unikernel specializes a minimalistic LibOS and a target application into a standalone single-purpose virtual machine (VM) running on a hypervisor, which is referred to as (virtual)
appliance
. ...Compared to traditional VMs, Unikernel appliances have smaller memory footprint and lower overhead while guaranteeing the same level of isolation. On the downside, Unikernel strips off the
process
abstraction from its monolithic appliance and thus sacrifices flexibility, efficiency, and applicability.
In this article, we examine whether there is a balance embracing the best of both Unikernel appliances (strong isolation) and processes (high flexibility/efficiency). We present KylinX, a dynamic library operating system for simplified and efficient cloud virtualization by providing the pVM (process-like VM) abstraction. A pVM takes the hypervisor as an OS and the Unikernel appliance as a process allowing both page-level and library-level dynamic mapping. At the page level, KylinX supports pVM fork plus a set of API for inter-pVM communication (IpC, which is compatible with conventional UNIX IPC). At the library level, KylinX supports shared libraries to be linked to a Unikernel appliance at runtime. KylinX enforces mapping restrictions against potential threats. We implement a prototype of KylinX by modifying MiniOS and Xen tools. Extensive experimental results show that KylinX achieves similar performance both in micro benchmarks (fork, IpC, library update, etc.) and in applications (Redis, web server, and DNS server) compared to conventional processes, while retaining the strong isolation benefit of VMs/Unikernels.
FreeBSD (an open source Unix-like OS) and Apple's Mac OS use similar BSD functionality but take different approaches. FreeBSD implements a traditional compact monolithic Unix kernel, whereas Mac OS ...builds the BSD Unix functionality on top of the Mach microkernel. The authors provide an in-depth technical investigation of both approaches.
