System & Network Admin

Recursion in programming is when a piece of code (usually a function) calls itself. If there is no exit case, the program will go on forever. We will be discussing recursion in a bash script with examples and discussing some peculiarities of the bash shell, such as local variables. Setup Let’s make a shell script.…

I want to do a function that will return the factorial of a number in bash Here's the current code that doesn't work, can anyone tell me what's wrong and how to correct it? I just started learning...

Learn how to use command-line arguments inside the bash script

rpm is a powerful Package Manager, which can be used to build, install, query, verify, update, and erase individual software packages.

Learn the most common ways of counting the number of lines of a specified file using Bash

Learn how to inspect and extract RPM package contents with working codes and examples in this article.

Here is my script: Get System info #!/bin/bash readarray -t array <<< "$(df -h)" var=$(echo "${array[1]}"| grep -aob '%' | grep -oE '[0-9]+') echo "${array[3]:$...

Bash scripts give you a convenient way to automate command line tasks. With Bash, you can do many of the same things you would do in other scripting or programming languages. You can create and use variables, execute loops, use conditional logic, and store data in arrays. While

Bash if statements. Learn if statements, else, elif and case statements with sample scripts, detailed descriptions and challenges.

In this tutorial, we are going to learn about how to get the first element of an array in Bash. Consider, we have the following array. Now…

Bash doesn't have a strong type system. To allow type-like behavior, it uses attributes that can be set by a command. ‘declare’ is a bash built-in command that allows you to update attributes applied to variables within the scope of your shell. In addition, it can be used to declare a variable in longhand. Lastly, it allows you to peek into variables.

In this quick tip, you'll learn to split a string into an array in Bash script.

In the first article in this series, you created a very small, one-line Bash script

ShellCheck finds bugs in your shell scripts

Journey on how UniFi Dream Machine Pro’s Dynamic DNS is setup and how to have it point to a custom Dynamic DNS provider.

Let's Encrypt is a new certificate authority. It is a huge improvement over the manual complex process of acquiring and …

When you get a certificate from Let’s Encrypt, our servers validate that you control the domain names in that certificate using “challenges,” as defined by the ACME standard. Most of the time, this validation is handled automatically by your ACME client, but if you need to make some more complex configuration decisions, it’s useful to know more about them. If you’re unsure, go with your client’s defaults or with HTTP-01.

In the following examples, I'll show how to renew certs with domains hosted on AWS/Route53 and GoDaddy. I run certbot with scripts within a docker container (to simplify automation), however you can use CLI.

How to obtain a Let's Encrypt certificate through a DNS Challenge.

My domain is: https://arenlor.com/ I ran this command: certbot certonly --rsa-key-size 4096 --staple-ocsp --server 'https://acme-v02.api.letsencrypt.org/directory' --dns-rfc2136 --dns-rfc2136-credentials /etc/letsencrypt/rfc2136.ini -d arenlor.com -d '*.arenlor.com' It produced this output: Saving debug log to /var/log/letsencrypt/letsencrypt.log Plugins selected: Authenticator dns-rfc2136, Installer None Obtaining a new certificate Performing the following challenges: dns-01 challenge for ar...

The sudoers file contains a set of rules that determines which users or groups are granted with sudo privileges as well as the level of the privileges.

If youre even a moderate Linux command line user, you must be aware of pipes, a fundamental command line feature that allows processes to communicate...

Benchmarks & Tips for Big Data, Hadoop, AWS, Google Cloud, PostgreSQL, Spark, Python & More...

There arent many viruses made for Linux distributions and as such, most people who use such systems dont even bother using antivirus software. Those...