Basic Nginx troubleshooting in Linux/Unix

This is a small post on how to start troubleshooting Nginx server. If you are facing an issue with nginx or any server/service the first thing to conform is if our configurations are correct or not. Nginx have two commands to show if there is any issue with your configuration or not. Checking your configs(…)

How to force logout a user from Linux/Unix servers

Today I come across a requirement where you have to force a user to logout from a terminal. When I contacted the user and he said he did not logged in. But the thing is I can see the login session from w, last commands. I did this checking before asking him. Then how can(…)

Linux/Unix: How to update timezone in a system

How to update time zone in Linux? Some times it is required to update our timezone when we move our machines(VMs) from one location to other. Recently I came across a situation where I want to move my machine time zone from IST to Sydney time zone. In this post we will see on how(…)

Linux/Unix: Sync system date/time with NTP server

How to sync system time with NTP server? This is small howto on how to setup ntp sync on a Linux box. Before going to do this we should know why we require to sync with NTP server. NTP is a network time protocol server used to sync time across the machines. When we setup(…)

How to get Linux Docker IP address

Docker is a high level framework for Linux containers which could be next level for virtualising applications and VM's. Some times it is require to get ip address of a docker so that you can try to check a service running on it or try to ssh at 22 port on the IP address assigned(…)

How to install and enable EPEL repo in RHEL/CentOS/Oracle Linux?

What is EPEL repo? EPEL(Extra Packages for Enterprise Linux) is a repo developed by Fedora project to ensure that there is a quality 3rd party packages available for enterprise users such as people who are using RHEL, Cent OS, Oracle Linux and Scientific Linux. These are highly used enterprise Linux OS which are shipped with(…)

Puppet: How to remove node from master

Q) How can I remove a register a puppet agent from puppet master? Some times it is required to remove a host(puppet node) from the register master. To achive this we have to run puppet cert command and have to manually remove entries from site.pp or other *.pp files where that host is register. This(…)

Puppet: List all the nodes in Puppet master

Q)Recently I installed couple of nodes and attached to Puppet master, How can I list all the nodes which are register with Puppet server?  Answer) There are couple of ways to list all the nodes register with master.  1)Through grepping node entries in /etc/puppet/manifests/site.pp(Though not a good way)  2)Through puppet cert command Listing entries though(…)

7 Linux/Unix gzip and gunzip command examples

This is our second post on compression and archiving series. Today we will see how to use gzip and gunzip commands with examples. Gzip(GNU zip) is a compress tool which is available in most of the Linux/Unix based operating systems. Until recent years gzip and bzip2 are most commonly used data compression tools in Linux/Unix. Though(…)

13 Zip and Unzip command examples in Linux/Unix

Zip is a compress tool which is available in most of the operating systems such as Linux/Unix, Apple OS, Microsoft OS etc. In this post we will see how to install, use and tips about zip command. How to install zip and unzip command in Linux? On Redhat, Centos and Fedora based machines yum install(…)