More Unix Command Example

8.if statement syntax: (for one-way Judgment branch) if list A then list B fi Example: if Test-s funfile then echo funfile exists fi echo Hello if structure is a value based on command return Process Control mode. If the test command returns a value of 0, a specified list of commands is executed, and if the command returned with a value other than 0, the specified command list is ignored ...

Calling the file system (FS) shell command should use the form of Bin/hadoop FS <args>. All of the FS shell commands use the URI path as a parameter. The URI format is Scheme://authority/path. For the HDFs file system, Scheme is HDFS, for the local file system, scheme is file. The scheme and authority parameters are optional, and if unspecified, the default SC specified in the configuration is used ...

By completing this chapter, you can do the following: Describe the functions of different network services understanding local area networks (LANs) in Unix find the host name of the local host and the hostname of the other system on the LAN. Use the Arpa/http://www.aliyun.com/zixun/aggregation/33795.html >berkeley service to perform remote logins, remotely file transfers, and remote command execution. 11.1 What is a LAN? The local area network (LAN) is in a small ...

We say that the main purpose of program debugging is to observe variable changes. But if the program keeps running until it stops or fails, there will be no chance to observe any variables. Therefore, how to effectively control the execution of the statements in the program, so that when the appropriate time to pause, the debugger to display or set the value of some of the storage unit and then continue from where to stop, is the debugger should have a basic function. In this section we will specifically describe how to control the operation of the program. The first problem with program execution control is to set breakpoints. A breakpoint ...

At present, in many business http://www.aliyun.com/zixun/aggregation/34332.html "> Processing system, network printer server has a wide range of applications, and these applications are based on the majority of TCP/IP protocol." 　Network print server is more common with Intel, Delink, Zot, and so on, the following small set on the Intel network print server as an example, to explain how to install the configuration network print server in Unix system. ...

&http://www.aliyun.com/zixun/aggregation/37954.html ">nbsp; The Windows PowerShell command prompt is a language that supports objects, and we can simply assign the result returned by the command to a variable, $files contains a collection of objects in the table of contents that are in the previous directory, and use the normal array access syntax to get the object at that location ....

GDB is a powerful UNIX program debugging tool released by the GNU Open source organization. Perhaps, you like the graphical interface, such as VC, BCB debugging IDE, but if you are in the UNIX platform to do the software, you will find that the debugging tool GDB is more than VC, BCB graphics debugger more powerful features. The so-called "inch, the ruler is short" is this truth. In general, GDB mainly help you to complete the following four aspects of the function: Start your program, you can follow the custom requirements of the arbitrary running of the program ...

This paper introduces how to build a network database application method by MySQL of the golden combination of Web database, PHP is a server-side embedded hypertext Processing language similar to Microsoft ASP, it is a powerful tool to build dynamic website. While MySQL is a lightweight SQL database server that runs on a variety of platforms, including Windows NT and Linux, and has a GPL version, MySQL is considered the best product for building a database-driven dynamic Web site. PHP, MySQL, and Apache are Linux ...

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 ...

In the past, we have introduced some principles of software development, such as the 10 commandments of high quality code and the UNIX design principles described in the UNIX legend (next article). I believe that you can learn from middle school some knowledge of design principles, as I said in the "How Do I Recruit procedures", a good programmer usually consists of its operational skills, knowledge level, experience level and ability four aspects. Here I would like to talk about some of the principles of design, I think these things belong to the long-term experience summed up knowledge. These principles should be understood by every programmer. But...