A regular expression is a pattern that describes a set of strings. Regular expressions are constructed analogously to arithmetic expressions by using various operators to combine smaller expressions. The fundamental building blocks are the regular expressions that match a single character. Most characters, including all letters and digits, are regular expressions that match themselves. Any metacharacter with special meaning may ...

In the past, I had tried to set up Docker during a few different programming competitions without ever having used it before. During the crunch time, I was unsuccessful in both setting it up and learning how it worked. But in those competitions I had the good fortune that my teammates were all able to configure their environment for the ...

Regardless the experience, every Linux user must has, at least, a basic knowledge about the terminal and its usage. This tutorial will explain and show with examples the most used and important commands, after a brief explanation of how the commands work. For this tutorial, Linux Mint 18 has been used. Table Of Contents 1. What are the commands? Where ...

In this article, I’ll review the necessary information for how to configure SNMP v1 options in a VMware vSphere ESXi host. If you also need to configure SNMP in a vCenter Server Appliance (vCSA), please check out my previous article: Configuring SNMP in a vCSA If you’re already familiar with SNMP, and you’ve already enabled SSH on your ESXi host, ...

This is a Bash Environment Variables Tutorial. There exists two types of variables: Global Variables Local Variables Global variables or environment variables are available in all shells. The env or printenv commands can be used to display environment variables. Local variables are only available in the current shell. Apart from dividing variables in local and global variables, we can also ...

Dealing with users is a task that every systems administrator has to deal with frequently. This example will show you how to delete users in Linux, looking at the two different available commands: The default utility, userdel; and a script that acts as more friendly front-end for the default utility, which is named deluser. For this example, Linux Mint 18 ...

In this article, we’ll review the necessary information for how to configure SNMP v1 options in a VMware vCenter Server Appliance.  If you’re reading this article, you likely already know what SNMP is, as well as how to utilize it.  If not, let me at least give you a brief intro, stating what it is and what it’s used for.  If you’re ...

In a recent article, I covered how to tune the NGINX webserver for a simple static HTML page. In this article, we are going to once again explore those performance-tuning concepts and walk through some basic tuning options for HAProxy. What is HAProxy HAProxy is a software load balancer commonly used to distribute TCP-based traffic to multiple backend systems. It ...

Course Overview PostgreSQL, often simply Postgres, is an object-relational database management system (ORDBMS) with an emphasis on extensibility and standards-compliance. As a database server, its primary function is to store data securely, and to allow for retrieval at the request of other software applications. It can handle workloads ranging from small single-machine applications to large Internet-facing applications with many concurrent ...