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At the same time, through the introduction of the following two examples, to consolidate the above problem analysis of the introduction: a multithreaded application of the performance problem analysis of a crash problem analysis of UNIX program http://www.aliyun.com/zixun/aggregation/17253. HTML > FAQ classification UNIX Run programs, often encounter the following types of problems: Crash memory leak handle leak process does not respond to the performance of the expected logic error UNI ...

By completing this chapter, you will be able to do the following: Understand the purpose of a pipe to create a pipe that obtains output from one command, and then manufactures input for another command using Tee,cut,tr,more, and PR filter 10.1 pipe profile shell provides the ability to connect commands through pipelines. The flexibility to reflect the operating environment of the UNIX system is fully filtered through the files. You can use pipelines to filter the output of a command. This chapter will introduce the use of pipes, and some filters (Cut,tr,tee and PR), which ...

To complete this chapter, you can do the following things: Describe and change the owners and groups of the files. Describes and changes permissions for a file. Describes and establishes default permissions for new files. Describes how to change the identity of users and groups of files. 5.1 File permissions and access access to a file requires the identity of the user and the permissions associated with the file. This chapter describes how to access file permissions to understand file read, write, and Execute permissions LS (ll,ls–l) determines the access permissions that the file is granted. chmod change file access permissions. Chown ...

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With the development of telecom industry, the competition among telecom operators has become fiercer. In order to win in the competition, the right business strategy becomes the key link of the telecom operator's success. Telecom operators have a large number of user data information, using data mining technology, can be in billing data, business order data, network management data, such as the mass user data found business knowledge, for the market to lay the foundation for precision marketing. With the expansion of China Mobile users and the diverse demands of application targets, data mining applications face new challenges. First of all, the user size is growing, by a large number of users produced a huge amount of data, including ...

Mac OS is the operating system that runs on Apple's Macintosh family of computers, and has been used by the industry to compare with Microsoft's Windows. Mac OS is the first commercially successful graphical user interface, when Mac OS launched a graphical interface, Microsoft remained in the DOS era, Windows is still in swaddling. 　　As Mac OS X Lion is about to launch, let's review the Mac OS's "Past and Present life". Mac OS can be divided into two of the operating system ...

Php:time (), date (), Mktime () php:time (), date (), mktime () Date and time function library {often forgets} Checkdate: Verify the correctness of the date. Date: Formats the time of the server. Strftime: Formats the server's time locally. GETDATE: Get time and date information. Gettimeofday: Get the current time. Gmdate: Get the present and ...

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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 ...

The DES (data encryption Standard) algorithm, which was formally licensed by the United States Government in 1977, is a method of encrypting 64-bit data with a 56-bit key. Des algorithms are applied to many situations where security encryption is required. (for example, the UNIX cipher algorithm is based on the DES algorithm). Here is a description of how to implement the DES algorithm language, if you want its source code, you can go to the http//assassin.yeah.net download, the latter you have any questions can also write to me (as ...)