nixCraft Linux & Unix Sysadmin/DevOps Tutorial Newsletter

[nixCraft]

Welcome to nixCraft Linux/Unix newsletter for Monday, 30 November 2020. I hope you will enjoy this version of the newsletter.

• Top 7 Linux GPU Monitoring and Diagnostic Commands Line Tools
  A video card is a special circuit board that controls what is displayed on a computer monitor. It is also called a graphics processing unit (GPU), which calculates 3D images and graphics for Linux gaming and other usages. Let us see the top 7 Linux GPU monitoring and diagnostic command-line tools to solve issues.
   
• Top 15 XKCD comics for Linux and Unix fans {trending}
  Linux is a free and open-source kernel developed by Linus Torvalds, a Unix-like operating system clone. XKCD comic has a long tradition for including humorous geeky cartoons. In this post, I pick my favorite XKCD comics for Linux and Unix fans.
   
• tmpmail – A temporary email right from Linux / Unix terminal {trending}
  Are you looking to send a temporary email right from your Linux or Unix terminal? Look no further. Try tmpmail command-line utility that allows you to generate a temporary email address for receiving emails. Underneath the script uses 1secmail's API to receive the emails.
   
• Linux set up bluetooth speaker to stream audio from your Android / iOS mobile phone {trending}
  So how do you stream audio from your Apple iOS or Google Android phone to your laptop speaker? Let us see how to set up a Bluetooth speaker to stream audio from your Android / iOS mobile phone to your Linux based laptop or desktop that got better audio speakers.
   
• Raspberry Pi 400 Desktop PC: Complete specs and pricing
  The Raspberry Foundation released a brand new version of the Raspberry PI PC (personal computer), and it is directly built into a small-sized keyboard. The Raspberry Pi 4 model was released in June 2019, and the 8GiB version recently. Let us see Raspberry Pi 400 technical specification and other details.
   
• How to convert pdf to image on Linux command line
  I have many PDF files, and I need to convert them to a png file format, add a border to those images, and convert back all those images to pdf format. How can I convert pdf to image format on Linux and vice versa using the CLI?
   
• How to install MySQL server on CentOS 8 Linux {trending}
  How do I install MySQL server 8.0 on CentOS 8 Linux server running on Linode and AWS cloud? How do I add and set up a new MySQL user and database account on the newly created CentOS server?
   
• How to install MySQL server on Debian 10 Linux
  How can I install MySQL server 8.0 on Debian 10 LTS Linux server? How do I add a new MySQL user and database on the newly set up Debian server running on AWS EC2 server?
   
• How to enable rc.local shell script on systemd while booting Linux system
  We can easily enable rc.local shell script support on systemd while booting the Linux system. Traditionally, the shell script /etc/rc.local used by developers and Linux sysadmin to call other scripts or commands after all services are loaded. Typically /etc/rc.local get called at the end when Linux init switched to a multiuser runlevel. However, by default. /etc/rc.local support is disabled under systemd. This page shows how to enable and execute rc.local shell script during boot using systemd on Linux.
   
• How to install VirtualBox on Ubuntu 20.04 Linux LTS
  How do I install VirtualBox application on Ubuntu 20.04 Linux LTS system?
   
• How to install MySQL server on Ubuntu 20.04 LTS Linux
  How do I install MySQL server 8.0 on Ubuntu 20.04 LTS Linux server? How can I add a new MySQL user and database on the newly set up Ubuntu server?
   
• How to check TLS/SSL certificate expiration date from command-line {trending}
  How do I check the TLS/SSL certificate expiration date from my Linux or Unix shell prompt? How can I find the TLS certificate expiry date from Linux or Unix shell scripts?
   
• How to show dropped packets per interface on Linux {trending}
  How do I display dropped packets per interface on Linux operating systems from the command line option? How can I determine why a Linux server is dropping packets?
   
• How to install dnscrypt proxy with adblocker on Linux {trending}
  How do I install the dnscrypt proxy application with an adblocker/malware blocker on Linux operating system with WireGuard or OpenVPN?
   
• How To Install Speedtest-cli On a FreeBSD To Check Internet Speed
  I am using the FreeBSD system. How do I install Speedtest-cli on a FreeBSD Unix system for checking the Internet speed?
   
• Alpine Linux set up WireGuard VPN server 
  How do I install and set up WireGuard VPN server on an Alpine Linux cloud server? How can I configure Alpine Linux as the WireGuard VPN server? How can I configure snat to route all VPN traffic on my Alpine Linux?
   
• How to disable firewall and NAT rules on the LXD bridge
  I followed your Ubuntu LXD tutorial, and I noticed LXD automatically created firewall and NAT rules. Is there any way to disable this feature? I want to manage a firewall using custom rule sets. How can I disable firewall and NAT rules on the LXD bridge under Linux?
   
• How To Set Up a Firewall with Awall on Alpine Linux {trending}
  Alpine Wall (Awall) is an easy to use interface to iptables for Alpine Linux users. While iptables and ip6tables is an excellent command, it can be challenging for new Alpine Linux users. The awall tool has easy to follow high-level concepts such as zones, limits, policies, and a single source for both IPv4 and IPv6. This tutorial will show you how to set up a firewall with Awall on Alpine Linux.

Until next time.

[nixCraft]

Welcome to nixCraft Linux/Unix newsletter for Thursday, 10 December 2020. I hope you will enjoy this version of the newsletter.

• CentOS Linux 8 will end in 2021 and shifts focus to CentOS Stream
  The free ride is over. Red Hat announced that CentOS Linux 8, as a rebuild of RHEL 8, will end in 2021. CentOS Stream continues after that date, serving as the upstream (development or beta) branch of Red Hat Enterprise Linux. CentOS 7 will end on 30/June/2024 too.
  
• How to create MySQL admin user (superuser) account
  Learn how to make a superuser (admin) with root-like access to the MySQL/MariaDB databases with secure plugins. Further, learn how to create an encrypted file to store admin user/password, host, and TLS info securely for ease of login via Linux/Unix CLI
  
• How to install Go [golang] on Ubuntu Linux
  Go lang is a trendy choice for DevOps, large scale distributed systems, cloud workloads, and system programming work. Let us see how to install Go on Ubuntu Linux
  
• How to supercharge string search through a directory hierarchy on a Linux/Unix using ag
  Usually, I use the grep command/egrep command for code searching on my box. Recently, I come across another cool tool called ag. It is an attempt to make something better than ack, which itself is better than grep command. Let us see how to install and use the ag tool on Unix-like operating systems.
  
• SSH ProxyCommand example: Going through one host to reach another server
  How do I use and jump through one server to reach another using ssh on a Linux or Unix-like systems? Is it possible to connect to another host via an intermediary so that the client can act as if the connection were direct using ssh? Can you give me SSH ProxyCommand and ProxyJump example?
  
• How To Set up OpenVPN Server In 5 Minutes on Ubuntu Linux
  I am a new Ubuntu Linux server user. How do I setup an OpenVPN Server on Ubuntu Linux version 18.04/20.04 LTS or 20.10 server to shield my browsing activity from bad guys on public Wi-Fi, and more?
  
• Linux ip Command Examples For Sysadmins and Developers
  The ifconfig command on Linux officially deprecated for some time. It is time to move on and learn the ip command. Let's see how to display, configure IP addresses, routing, links, and more associated with network interfaces on Linux using the ip command.
  
• Linux: How To Encrypt And Decrypt Files With A Password
  Where security is critical, we use strong encryption such as Pretty Good Privacy/GNU PGP instead of the relatively weak standard encryption provided by many CLI utilities. Let us see how to encrypt and decrypt files on Linux and Unix command-line.
  
• How To Use Bash Parameter Substitution Like A Pro
  The $ character is used for parameter expansion, arithmetic expansion and command substitution. You can use it for manipulating and expanding variables on demands without using external commands such as perl, python, sed or awk. This guide shows you how to use parameter expansion modifiers to transform Bash shell variables for your scripting needs.
  
• VI / VIM - Open File And Go To Specific Function or Line Number
  How do I open a text file using VIM or VI and go to specific line? How do I open a file using vim and go to specific function() in my source code?
  
• How To Configure Firewall with UFW on Ubuntu 20.04 LTS
  UFW is an acronym for an uncomplicated firewall. Securing a network with an uncomplicated firewall is super easy and highly recommended. It allows you to protect the server from bad guys, and you can open or close ports, ban IP addresses and limit ssh access and much more quickly. Let us see how to set up and use ufw on Ubuntu 20.04 LTS server.
  
• How to improve your bash/sh shell script with ShellCheck lint script analysis tool
  ShellCheck is a static analysis tool for shell scripts. One can use it to finds bugs in your shell scripts. It is written in Haskell. You can find warnings and suggestions for bash/sh shell scripts with this tool. Let us see how to install and use ShellCheck on a Linux or Unix-like system to enhance your shell scripts, avoid errors and productivity.
  
• Linux / UNIX Desktop Fun: Terminal ASCII Aquarium
  You can now enjoy mysteries of the sea from the safety of your own terminal using ASCIIQuarium. It is an aquarium/sea animation in ASCII art created using perl.
  
• Getting Yesterday's or Tomorrow's Day With Bash Shell Date Command on Linux / Unix
  When invoked without arguments, the date command displays the current date and time. Depending on the options specified, the date would set the date and time or print it in a user-defined format. However, how do you get yesterdays with bash shell script? What about tomorrow's day?
  
• How to Install Java on Ubuntu 20.04 LTS Linux
  Java is one of the most popular software and specifications initially created by James Gosling at Sun Microsystems. We can create a cross-platform application in Java for mobile phones or desktop users. Let us see how to install Java Runtime Environment (JRE) and Java Development Kit (JDK) on Ubuntu Linux 20.04 LTS.
  
• How to create a Linux swap file
  I am a new Linux system developer and user. How do I create a Linux swap file from the command line option for my cloud server? How can I add swap space on my Ubuntu 20.04 LTS or CentOS Linux 7/8 server?
  
• How to check if CentOS / RHEL needs a full reboot
  I am using a CentOS/RHEL 6/7/8 server. How do I check from the command line if a reboot is required for my CentOS host? How do I check if a host powered by CentOS Enterprise Linux needs to reboot after running the yum update command?
  
• How to use ssh-agent for authentication on Linux / Unix
  How do I use the ssh-agent command for non-interactive authentication on Linux and Unix-like systems such as macOS or FreeBSD desktop? My private key is protected with a passphrase or password. So I need to enter the passphrase to use the ssh private key for authentication multiple times. How can I tell ssh ask the passphrase one time only?
  
• FreeBSD configure AWS SES with Postfix MTA
  How do I integrate and configure Amazon/AWS SES with Postfix running on my FreeBSD Unix server?
  
• UNIX / Linux PGP TarBall File Signature Keys Verification
  For all FOSS based project, you should download the PGP signatures and MD5/SHA hashes and verify them before using them for security reasons. Learn how to verify the PGP key against downloaded software under Linux / UNIX / *BSD and macOS using the GNU Privacy Guard or any OpenPGP-compliant program.