nixCraft Linux & Unix Sysadmin/DevOps Tutorial Newsletter

[nixCraft]

Welcome to nixCraft Linux/Unix newsletter for Thursday, 27 August 2020. I hope you will enjoy this version of the newsletter.

• How to backup and restore LUKS header on Linux
  Previously I explained how to encrypt Linux partitions or disk with the LUKS (Linux Unified Key Setup)/dm-crypt. In this quick blog post, I will explain how to backup and restore LUKS header for emergency purposes. Backup is useful for recovering from misconfigurations, corrupted headers or forgotten passphrase or unknown password.
   
• bashtop - Awesome Linux resource monitor {trending}
  There is a new kid in town for resource monitoring on Linux called bashtop. As the name suggests, the entire tool coded in the bash script itself that displays usage and stats for CPU, RAD, HDD/SSD, network, and other resources. Let us see how to install and use bashtop, which is an awesome Linux resource monitor. You don’t need a Linux desktop to install it. You can also install this app on macOS/FreeBSD provided that you meet software requirements.
   
• 10 Linux commands to know the system {trending}
  Here are 10 Linux command to know the system and increase your productivity quickly.
   
• Linux Slimbook Laptop with AMD Ryzen 4000 released
  KDE project and Slimbook released a new Linux ultrabook with AMD Ryzen 4000 CPU that comes with eight cores, 16 threads, and a Plasma desktop. Let us look into Linux Slimbook Laptop hardware specifications and other information.
   
• How to push/send message to iOS and Android from Linux CLI {trending}
  One of the essential tasks for developers and sysadmin is to get an alert notification about failed services or running out of disk space and other critical failures. Let us see how to send or push a direct message to a mobile device powered by Apple iOS or Google Android phone.
   
• CentOS Linux 8.2 (2004) released and here is how to upgrade it
  CentOS Linux 8.2 (2004) released. It is a Linux distribution derived from RHEL (Red Hat Enterprise Linux) 8.2 source code. CentOS was created when Red Hat stopped providing RHEL free. CentOS 8.2 gives complete control of its open-source software packages and is fully customized for research needs or for running a high-performance website without the need for license fees. Let us see what’s new in CentOS 8.2 (2004) and how to upgrade existing CentOS 8.1.1199 server to 8.2.2004 using the command line or bash prompt.
   
• 8GB Raspberry Pi 4 released for $75 – Specifications
  Back in June 2019, the Raspberry PI 4 model was released, and it was an incredible update over the older model with up to 4GB ram. Today we see the long-rumored 8GB Raspberry Pi 4 released and priced at the just US $75. Here are the complete specs for an updated 64-bit credit card size Raspberry PI 4 8GB model with Linux desktop computer level of performance.
   
• How to view status of a service on Linux using systemctl
  Learn how to use the systemctl command to view status of a service on Linux operating systems for debugging purposes?
   
• How to save iptables firewall rules permanently on Linux
  Explains how to store iptables IPv4 and IPv6 rules permanently on the Debian/Ubuntu/RHEL and CentOS Linux cloud server
   
• How to install less on CentOS / RHEL / Fedora {trending}
  Are you missing less command on your CentOS/RHEL/Fedora Linux cloud server? Here is how to install it manually using CLI or bundle with your Docker/Podman based Linux container using Dockerfile
   
• How to write the output into the file in Linux
  I/O redirection for both bash and POSIX shell to write data to the file under Linux or Unix-like systems.
   
• How to set/change FQDN on Ubuntu 20.04 Linux
  How do I set/change my server’s Fully Qualified Domain Name (FQDN) on Ubuntu 20.04 LTS "Focal Fossa" Linux?
   
• How to add days to date and get new date on Linux
  I brought eggs from the market, and it says best before 20 days from the date of packing. Say my egg box was packed on 29/July/2020. How do I add days to date using Linux CLI? I want to find out date 29/July/2020 + 20days using the CLI, and how do I do it?
   
• Set up automatic unattended updates for Ubuntu 20.04
  Learn how to automatically apply security updates when released by the Ubuntu security team using an unattended-upgrades method for the Ubuntu 20.04 LTS server to keep your box secure.
   
• How to install KVM on Ubuntu 20.04 LTS Headless Server {trending}
  Kernel-based Virtual Machine (KVM) is a virtualization module for the Linux kernel that turns it into a hypervisor. How can I install KVM with bridged networking, set up a guest operating system as the back-end virtualization technology for non-graphic Ubuntu Linux 20.04 LTS server over ssh based session?
   
• Ubuntu 20.04 add network bridge (br0) with nmcli command
  How do I configure my Ubuntu 20.4 LTS and add network bridge (br0) with the nmcli command? How can I create a Linux network bridge on Ubuntu Linux 20.04 LTS server for KVM (Kernel-based Virtual Machine)?
   
• How to install htop on Arch Linux
  I am a new user of Arch Linux operating system. How do I install htop on Arch Linux using the pacman command?
   
• Squid test config file for syntax errors
  I installed Squid Proxy server on Ubuntu 20.04 LTS. How do I make sure my squid.conf file is free from syntax errors and test config file for errors?
   
• How to install a Wireguard VPN client in a FreeBSD jail
  I installed/set up a Wireguard VPN server on Debian 10 Linux box. How do I install, configure and set up a Wireguard client in a FreeBSD jail?
   
• apt-get hold back packages on Ubuntu / Debian Linux
  How do I hold back packages on an Ubuntu / Debian Linux to prevent updating of a specific package? How can I blacklist package updates using the apt command/apt-get command?
   
• Route 53 Let’s Encrypt wildcard certificate with acme.sh {trending}
  How do I get a wildcard TLS/SSL certificate from Let’s Encrypt using acme.sh and AWS Route53? How can I set up wildcard Let’s Encrypt SSL with AWS Route53 for Nginx or Apache?

Until next time.