How to Grep Multiples Lines and using Specific Keyword on Linux


grep is a command line text search utility originally written for Unix or linux. In linux you can grep multiple lines before or after matching the keywords. This examples has been tested on linux CentOS 6.2, but it may workings on other linux version such as Redhat Enterprise Linux 5 (RHEL5) or (RHEL6). Get grep […]

How to Open the File in Read Only Mode on Linux


Question : How to open a file on read only mode on linux? Answer : This command has been tested on Redhat Enterprise linux 6 (RHEL6) server. To open the file with vim in read only mode on linux, you need to run “vim -R” as below. Vim is enhanced version of vi editor that […]

How Display Logged in User Information and Terminal number on Linux Server


In this post i will show on how to display logged in user information and terminal number on Linux server. This post provides practical examples for future references. This steps has been tested on Redhat Linux Enterprise server 6 and may working CentOS server as well. 1. “who am i” command is use to display […]

How to Check Memory and I/O with vmstat on Linux CentOS 5/CentOS 6/RHEL 5/RHEL 6 server – System Performance


vmstat command is a utility that will provides interesting information abaout processes, memory, i/O and CPU activity. When you run vmstat utility command without any arguments, you will see the output as below. This post will guide you on how to check memory and I/O with vmstat on Linux CentOS 5/CentOS 6/RHEL 5/RHEL 6 server […]

How to Track System Activity With top Command on Linux CentOS 5/CentOS 6/RHEL 5/ RHEL 6 server – System Performance


Top command is utility to monitor system activity interactively. When you run top from shell window, it will display all the activity processes and updates the screen. In this post i will show the usage of top command on CentOS 5/CentOS 6/RHEL 5/ RHEL 6 server to keep track system activity and to optimize the […]

How to Backup and Restore MySQL Database on CentOS/RHEL


In this post, i will share on how to backup and restore MySQL database on Linux server. I have tested this on my CentOS and RHEL servers. MySQLDump — A Database Backup Program, Click for more info. The mysqldump client is a backup program originally written by Igor Romanenko. It can be used to dump […]

How to Install telnet on CentOS

Question : When i try to perform the troubleshooting using telnet command, the following error appeared. How to fix this ? [root@centos62 ~]# telnet localhost 25 -bash: telnet: command not found Answer : Simply install telnet using this command : [root@centos62 ~]# yum install telnet Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile * […]