This tutorial explains the process of building useful multi­-part commands piece by piece.

To build complex commands in the terminal, we need to understand piping. Piping is basically taking the output of one command and sending it to another command as input. This is done with the | (pipe) symbol.

Last month, a small project required me to repeatedly read similar XML files to provide test data for another program. I would have to do it so frequently that it would be annoying to have to download, save, parse and repeat. The basic requirements were:
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Wireshark is an open source network packet analyzer.

It can capture, dissect, and decode various protocols. This helps Linux sysadmin to troubleshoot network issues.

Apart from using wirehshark as a standlone application for debugging network packets, you can also write your own extension or plugin using wireshark libraries for your custom application.

This tutorial explains how to use wireshark libraries to write custom code to debug network packets using a C example program.
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As a Linux Sysadmin, you might still find yourself managing few Windows Servers.

In those situations, instead of using the Windows GUI for administration, you might find it interesting to install and configure Windows Services from command line.

In this tutorial, we’ll explain how to install AD (Active Directory) on Windows 2012 Core Servers using the following command line utilities.

  • install-windowsfeature
  • import-module
  • install-addsforest

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logstash-logoLogstash is an open source central log file management application.

You can collect logs from multiple servers, multiple applications, parse those logs, and store it in a central place. Once it is stored, you can use a web GUI to search for logs, drill-down on the logs, and generate various reports.

This tutorial will explain the fundamentals of logstash and everything you need to know on how to install and configure logstash on your system.
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If you try to solve some combination problem in programming using simple combination approach where you check all possible variations with repetition or permutations of some kind, you would realize that you would have way too many tries that are not necessary.

You should reduce the poll of possible candidates as much as you can, and find a better solution that will use less processor time.

One of possible technique to solve a combination problem is to use backtracking.
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How to Install BIRT Viewer Runtime for Apache Tomcat in Linux

by Ramesh Natarajan on December 3, 2014

BIRT is an open source reporting engine that is based on Java technology. This is one of Eclipse top level project.

The following are two major components of BIRT:

  1. BIRT Report Designer – You can design rich reports using this designer UI from Eclipse. The report design is stored in an XML format.
  2. BIRT Viewer – This runtime viewer helps you to execute the report against any dataset. You can view the reports directly from Eclipse. Or, you can deploy the report as Apache Tomcat webapp, and view it from a web browser.

Birt Viewer helps developers to embed reports inside custom application. BIRT viewer supports various report output format including HTML, PDF, XLS, DOC, power point, postscript, etc.
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7 Patch Command Examples to Apply Diff Patch Files in Linux

by Lakshmanan Ganapathy on December 2, 2014

When there is a security fix available for a particular software, we typically do a binary upgrade using the package management tools like yum or apt-get.

But, there might be situation where you have installed a software by compiling it from the source code.

In those situation, how do you apply the security fix to the software?

The answer is to download the security patch and apply it to the original source code and re-compile the software.

This tutorial explains how to create a patch file using diff, and apply it using patch command.
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How to Restore Oracle Database using RMAN (with Examples)

by Ramesh Natarajan on November 24, 2014

As a Linux sysadmin, you might recover a system from backup, which may include Oracle Database.

So, it is essential for all admins to understand how to restore oracle database from backup.

Typically, DBAs will use Oracle RMAN utility to take a hot backup of the database.

This tutorial provides an introduction on how to restore an Oracle database from the RMAN backup.
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