Author Archive: Raghu

Raghu is working as Linux Server Administrator in Acknown Technologies Pvt. Ltd. He has been using Linux from last 5 years. He completed his RHCE certification in 2009. He likes to read about Linux and other Open Source Technologies and write articles on these.

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5 Steps to Setup MySQL Master-Master Replication on Ubuntu 16.04

The Master-Slave replication in MySQL databases provides load balancing for the databases. But it does not provide any failover scenario. If the Master server breaks, we cannot execute queries directly on the slave server. In addition to load balancing, if we need failover in our scenario, we can setup 2 MySQL instances in Master-Master replication. […]

Posted on : June 30, 2016 By
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Awesome ! systemd Commands to Manage Linux System

Systemd is the new system and service manager for Linux. It is a replacement for init system and can manage system startup and services. It starts up and supervises the entire system. In article we are using centos 7.0 installed with systemd 216 version and the latest version is available for download from With new […]

Posted on : August 29, 2014 By
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How To Install / Upgrade systemd on RHEL/CentOS 7.0

Centos/RHEL already adopted using systemd from version 7.0. In this article, we explore how this new upgrade release systemd 216 can be installed. The new release of systemd brings some new features. New commands like networkctl are introduced in this new version. 1. Check Current systemd Version First of all, we proceed with checking the […]

Posted on : August 25, 2014 , Last Updated on : August 25, 2014 By
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8 Options to Trace/Debug Programs using Linux strace Command

The strace is the tool that helps in debugging issues by tracing system calls executed by a program. It is handy when you want to see how the program interacts with the operating system, like what system calls are executed in what order. This simple yet very powerful tool is available for almost all the […]

Posted on : August 18, 2014 By
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How to Merge Directory Trees in Linux using cp Command

How to merge two directory trees with similar layout into a third directory? Let us consider the following example to understand the problem. Suppose two directories dir1 and dir2 have 3 sub-directories a, b and c in each of them. The directory layout is like below: These directories a, b and c have some files in […]

Posted on : July 23, 2014 , Last Updated on : July 23, 2014 By
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Linux slabtop command - Display Kernel Slab Cache Information

The Linux kernel needs to allocate memory for temporary objects such as task or device structures and inodes. The caching memory allocator manages caches of these types of objects. The modern Linux kernel implements this caching memory allocator to hold the caches called the slabs. Different types of slab caches are maintained by the slab […]

Posted on : July 11, 2014 By
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Linux chpasswd Command - Change Passwords in Bulk Mode

Creating users and managing passwords is one of the primary responsibilities of a system administrator. A good policy requires modification of passwords on regular intervals. But changing the passwords for a number of users with passwd command becomes difficult. In this article we provide a method to change the passwords in batch mode. 1. The […]

Posted on : July 7, 2014 , Last Updated on : July 9, 2014 By
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Power of Linux wget Command to Downloand Files from Internet

Wget is the command line, non interative , free utility in Unix like Operating systems not excluding Microsoft Windows, for downloading files from the internet. Most of the web browsers require user's presence for the file download to be completed. But wget allows users to start the file retrieval and disconnect from the system. It […]

Posted on : February 24, 2014 , Last Updated on : February 22, 2014 By
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Understanding Linux cd Command with Examples

The cd command is the most basic command in *nix world. What linux cd command does is it changes your current working directory. This article details about this command, what this command can do and the internals about the command. cd command: An internal command The BASH shell is the default shell in most Linux […]

Posted on : December 26, 2013 By
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30 Linux TOP Command Usage Examples for Monitoring

The top command in Linux displays the running processes on the system. One of the most important tools for a system administrator. It is used extensively for monitoring the load on a server. In this article, we explore the top command in detail. The top command is an interactive command. Many commands are available when […]

Posted on : November 28, 2013 , Last Updated on : April 13, 2017 By
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Install Cinnamon 2.0 on Ubuntu

Cinnamon is the desktop environment forked from gnome shell, developed by Linux Mint team. The GNOME 3's new interface gnome shell did not recieve much acceptance from Linux users as expected. The Ubuntu developers tried making some modifications to the GNOME shell to provide Unity. But many users have stuck with gnome-clasic. The Cinnamon desktop […]

Posted on : November 4, 2013 , Last Updated on : December 9, 2013 By
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How To Install And Configure Multi Router Traffic Grapher (MRTG) in Linux

MRTG is an open source network traffic monitoring tool. It creates png images in the form of graphs that show the traffic load of network nodes. MRTG works on SNMP protocol to request from the nodes. So the devices monitored by MRTG must be SNMP enabled. Many managed switches and routers are SNMP enabled. MRTG […]

Posted on : October 31, 2013 , Last Updated on : December 9, 2013 By
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Linux Change File / Directory Ownership - Chown Command

The files, directories and processes (which are again files) in Linux are owned by users. They have a group owner. The owner and group ownership is important as the security of files through permissions (the DAC) is set on owner, group owner and others. The chown command can change the ownership and group ownership of […]

Posted on : September 5, 2013 , Last Updated on : November 23, 2013 By
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A Freshers Guide for Linux chmod Command to Change File Permissions

The Linux security starts with file permissions. On the very basic level, file and directory permissions play a vital role in the security of a system. When you create a file or directory on Linux systems, it comes with default permissions. The file permissions are applied on three levels: the owner, group members and others. […]

Posted on : September 2, 2013 , Last Updated on : May 17, 2017 By
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