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preface AWK is an interpretive programming language. For text processing, its first name comes from the last names of its three authors: Alfred Aho, Peter Weinberger and Brian Kernighan awk program structureRun awk file scriptawk basic syntaxBuilt in variables commonly used in awk program Pay attention to the official account and exchange wi ...

1, Background of the incident One day last month, due to the lack of cluster space, an employee with higher authority in the company executed the manual cleaning command on an online cluster through the springboard machine and frantically executed hadoop fs -rmr -skipTrash /user/hive/warehouse/xxxxx. Suddenly, I didn't know whether it was the ...

Cluster is a kind of computer system, which is connected by a group of loosely integrated computer software and / or hardware to complete the computing work with high close cooperation. In a sense, they can be regarded as a computer. A single computer in a cluster system is usually called a node and is usually connected through a local area net ...

Original: enjoy learning classroom lecturer Reprint, please state the source! For example, frameworks that handle large amounts of information, such as Spring batch processing, use threads to manage data. Operating threads or CPU processes at the same time can improve performance, resulting in faster and more efficient programs. W ...

Today, the little assistant of positive motion will share with you how the ECI2828 of EtherCAT motion control card uses C# to synchronize PWM output with analog output and motion speed. The application scenarios of this paper include the energy control of laser cutting and laser marking and other applicable scenarios. I. Introduction to ECI282 ...

preface maven is the most popular project construction system. If it is java related development, it can be said to be indispensable. Although another module management tool grade is emerging, maven is still commonly used by most companies Maven and Maven's warehouseMaven command and build lifecyclemaven project POM Detailed explanation of XM ...

I woke up early today and was a little closer to my goal. The painful conversation time was almost over. All that remained was to finish the work and wait patiently. Although the result was not necessarily the same as I imagined, some changes were also good. I finished a hard question for the first time. Although I spent a lot of time and look ...

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preface In Java, we are familiar with locks. The commonly used locks are synchronized and Lock. In Java Concurrent Programming, we use locks to solve the problem of data inconsistency caused by multiple threads competing for the same shared resource or variable. However, JVM locks can only be used for a single application service. With the d ...

#1. Characteristics of string ##1.1 invariance We often hear that the key of HashMap suggests using immutable classes, such as String. Immutability here means that once the class value is initialized, it can no longer be changed. If it is modified, it will be a new class. Let's write a demo to demonstrate it. public class test { public sta ...