Unix Shell While

By completing this chapter, you will be able to do the following: Describes the effect of a return value in a conditional branch statement. Use the test command to parse the return value of a command. Use the IF and case structures in a shell program. &http://www.aliyun.com/zixun/aggregation/37954.html ">nbsp;1. Return value shell variable"? "To save the return value of the last executed command: 0: ...

By completing this chapter, you will be able to do the following: Use the while statement to repeatedly execute a piece of code when the condition is true. Use the loop statement to repeatedly execute a piece of code until the condition is true. Use the interactive for statement for loop control. 1. Brief introduction to the loop objective: Repeat the execution of a list of commands. control; a return value based on a key command. Three forms: While ... do ... do loop ... do ... do.

Bash (GNU bourne-again shell) is the default shell of many Linux platforms, in fact, there are many traditional Unix shell, like tcsh, CSH, Ash, BSH, Ksh, and so on, SHell script is roughly similar, When you learn a shell, the rest of the shell will soon start, and most of the time, a shell script can often be used on many kinds of shells. By learning how to use bash scripting ...

The simplest way to compromise is to have your password written somewhere, and there is no guarantee that no one else can see it except you. If someone gets your password and your private key file, the entire encryption system will be silent. Another old topic is the password not too simple, note that PGP is "password" passphase, rather than "password" password that is, you can include multiple words and spaces in the password. A wily attacker may use a famous book to find your password. So in order to get a good and difficult to guess password, you can sporogenous some sentences or find ...

This paper is an excerpt from the book "The Authoritative Guide to Hadoop", published by Tsinghua University Press, which is the author of Tom White, the School of Data Science and engineering, East China Normal University. This book begins with the origins of Hadoop, and integrates theory and practice to introduce Hadoop as an ideal tool for high-performance processing of massive datasets. The book consists of 16 chapters, 3 appendices, covering topics including: Haddoop;mapreduce;hadoop Distributed file system; Hadoop I/O, MapReduce application Open ...

MySQL has become one of the most widely used databases in the current network, especially in Web applications, which occupy the absolute advantage of small and medium applications. It all stems from its compact, safe, efficient, open licensing and multi-platform, and, more important, the perfect combination of--php with one of the three web languages. Unfortunately, a default installation of MySQL, because the root password is empty and the program vulnerabilities caused by the overflow, so that the installation of MySQL server is a frequent target. What is more serious is that the database is often destroyed after the attack, causing disaster easily ...

"Editor's note" Shopify is a provider of online shop solutions company, the number of shops currently serving more than 100,000 (Tesla is also its users). The main frame of the website is Ruby on rails,1700 kernel and 6TB RAM, which can respond to 8,000 user requests per second. In order to expand and manage the business more easily, Shopify began to use Docker and CoreOS technology, Shopify software engineer Graeme Johnson will write a series of articles to share their experience, this article is the department ...

Erecting a FTP server is actually very simple. First of all, to ensure that your machine can access the Internet, but also not less than ADSL 512Kbps network speed. Second, the hardware performance to meet your needs. Finally, you need to install FTP server-side software, such a lot of software, you can use Microsoft's IIS (Internet Information Server Internet Information Services), you can also use the professional software. Different software to provide different functions, adapt to the needs and operating systems are also different. In general, the system minimum requirements such as ...

Now let's do something interesting! We will create an SE Linux user and assign him a role and then set the default security context for the user. In the old SE Linux environment, the encapsulation program was set up with VIPW (SVIPW), for example, Useradd (Suseradd), passwd (SPASSWD), CHFN (SCHFN), and so on, in the new SE linux environment, These programs have other names. 5.1 Establish a new ...

Linux Container runtime docker open source published 15 hours ago | Times Read | SOURCE csdn| 0 Reviews | The author Zhang Hong month Open source Linuxdocker Summary: Docker is a http://www.aliyun.com/zixun/aggregation/13423.html "> Cloud computing Platform, it utilizes Linux lxc, Aufu, Go language, Cgroup to achieve the independence of resources, can be very easy to achieve file, capital ...