Linux

Bash has several commands that comes with the shell (i.e built inside the bash shell). When you execute a built-in command, bash shell executes it immediately, without invoking any other program. Bash shell built-in commands are faster than external commands, because external commands usually fork a process to execute it. In this article let us [...]

You might find the following three Linux / Unix shell scripts helpful. Display processes based on either %CPU or Memory Usage. Display which user is utilizing the CPU the most. Display system’s memory information – total, used and free. 1. List Processes based on %CPU and Memory Usage This script list the processes based on [...]

When I drafted this article, I really came-up with 7 sysadmin habits. But, out of those 7 habits, three really stood out for me. While habits are good, sometimes rules might even be better, especially in the sysadmin world, when handling a production environment. Rule #1: Backup Everything ( and validate the backup regularly ) [...]

In bash shell, when you use a dollar sign followed by a variable name, shell expands the variable with its value. This feature of shell is called parameter expansion. But parameter expansion has numerous other forms which allow you to expand a parameter and modify the value or substitute other values in the expansion process. [...]

Question: While downloading using wget, I get the following error “Connecting to <URL>.. failed: Connection refused.”. I’m behind a proxy server. How do I fix it? Answer: Export the http_proxy variable with your proxy server name or ip address and then try downloading as explained below. Connection refused error while using wget If http_proxy environment [...]

In this article, let us discuss about how to setup tftpboot, including installation of necessary packages, and tftpboot configurations. TFTP boot service is primarily used to perform OS installation on a remote machine for which you don’t have the physical access. In order to perform the OS installation successfully, there should be a way to [...]

On Linux, you can setup disk quota using one of the following methods: File system base disk quota allocation User or group based disk quota allocation On the user or group based quota, following are three important factors to consider: Hard limit – For example, if you specify 2GB as hard limit, user will not [...]