Sed is a stream editor in a UNIX-like operating system that is used for filtering and transforming text. Sed is derived originally from the basic line editor ‘ed’, an editor you will find on every Unix system but one that is rarely used because of its difficult user interface. How sed Works? As sed is […]
DevOps
Puppet Server’s Resources Cheat Sheet with Examples
Puppet is an open-source configuration management tool from Puppet Labs. Puppet Resources are the building blocks that puppet uses to model system configurations. The most common Puppet’s Resources are Listed below. file resource Manages local files. Example of file resource is mentioned below: file { ‘/etc/sudoers’: ensure => file, group => ‘root’, owner => ‘root’, […]
Backtick (`) symbol in Linux Shell Scripting
One of the most useful features of shell scripts is the lowly back quote character, usually called the backtick (`) in the Linux world. Be careful—this is not the normal single quotation mark character you are used to using for strings. Because it is not used very often outside of shell scripts, you may not […]
How to Start, Stop and Restart Zimbra Service
The Zimbra server contains Postfix, MySQL, OpenLDAP, ClamAV, and Spam-Assassin, Calendar, and various other features. Zimbra provides a paid option as well as an open source version. The first command in Zimbra mail server which we need to care about zimbra server service status. All services should be running on server. If any of service […]
How to Find and Delete Empty Directories and Files in Linux
1. Find empty directories in the current directory using find -empty: $ find . -type d -empty 2. Use the following command to remove all empty directories under the current directory: $ find . -type d -empty -exec rmdir {} \; 3. Find empty files in the current directory using find -empty: $ find . […]
How to change the audit log path in the MySQL Docker
1. Here we use 5.7.29 Docker image as an example. $ docker load -i mysql-enterprise-server-5.7.29.tar 2. You can bind OS mounts to Docker directory, assume you want to keep the audit logs under /bak/logs directory on the host. $ docker run –name=mysql1 \ –mount type=bind,src=/bak/my.cnf,dst=/etc/my.cnf \ –mount type=bind,src=/bak/data,dst=/var/lib/mysql \ –mount type=bind,src=/bak/logs,dst=/var/lib/logs \ -d mysql/enterprise-server:5.7 3. […]
“Error: Could Not Find A Ready Tiller Pod” – helm error
The Problem Getting “Error: could not find a ready tiller pod” error when trying various helm commands. > helm version Client: &version.Version{SemVer:”v2.14.3″, GitCommit:”0e7f3b6637f7af8fcfddb3d2941fcc7cbebb0085″, GitTreeState:”clean”} Error: could not find a ready tiller pod The Solution This error is caused due to wrong configuration or version mismatch. Follow the procedure to install helm and tiller using the […]
How to schedule master node running pod/service as worker node
Question: How to Schedule Master Node to Run Pod Workloads Like the Worker Node? By default, only the worker node can run the pod workloads and the master is only responsible for the scheduling and configuration. $ kubectl get nodes -o json | jq .items[].spec.taints [ { “effect”: “NoSchedule”, “key”: “node-role.kubernetes.io/master” } ] $ kubectl […]
Python Quadratic Formula
An equation with the form ax^2+bx+c=0 is known as a quadratic equation. When plotted on a graph it will take the general shape of the graph seen below. The points at which the quadratic graph crosses the x-axis are known as the solutions of the quadratic equation. For this example, the quadratic crosses the x-axis […]
How to Check if the script is run by root at the start of the script
Check root at start of script Some scripts need to be run as root and you may want to check at the start of that script that it is running as root. This can be done by checking the environment variable $EUID. This variable will hold the value 0 if it’s being run as root. […]