nixCraft Linux & Unix Sysadmin/DevOps Tutorial Newsletter

[nixCraft]

Welcome to nixCraft Linux/Unix newsletter for Monday, 24 May 2021. I hope you will enjoy this version of the newsletter.

• RHEL 8.4 released and here is how to upgrade 8.3 to 8.4
  Red Hat Enterprise Linux (RHEL) 8.4 released. This version includes updates and various improvements for developers, hybrid cloud, edge deployments and more.
  
• Quick Tip: Turn off the login banner in Linux or Unix .hushlogin file
  Did you know? You can turn off the banner in Linux or Unix using a particular file. When you log in using ssh or other methods, you will find tons of information on the screen.
  
• Interview with Michael Lucas *BSD, Unix, IT and other books author
  Michael Lucas is a famous IT book author. Perhaps best known for FreeBSD, OpenBSD, and Unix book series. He worked as a system administrator for many years and has now become a full-time book writer. Lately, I did a quick Q and A with Michael about his journey as a professional book author and his daily workflow for writing books.
  
• FreeBSD 13 released: Here is how to upgrade FreeBSD 12 to 13
  The FreeBSD project released FreeBSD version 13. The new version comes with updated software and features for a wild variety of architectures. The latest release provides performance improvements and better support for FreeBSD. One can benefit greatly using an upgraded version of FreeBSD. Let us see what’s new and quickly update FreeBSD 12 to 13 using the CLI.
  
• How to set up ZFS ARC size on FreeBSD
  When working with FreeBSD and ZFS, you will run into ZFS cache size problems. Not all FreeBSD servers are file servers. Some servers act as backup servers. Others might run Linux and Windows VM where you want those guest VMs to manage their own caching. It would help if you had tons of RAM for ZFS, but you may not have that luxury in real life. This page explains how to set up ZFS arc size on FreeBSD to work with less RAM to avoid the computer running out of memory in the kernel.
  
• How To Update Samsung SSD Firmware on Linux
  Typically, we apply firmware updates to fix a security issue and enhance SATA/PCIe/NVMe solid-state (SSD) drive performance. Failing to install available updates may lead to vulnerable SSD. This quick guide explains how to update Samsung SSD firmware on Linux without using Windows operating system.
  
• How to use df command in Linux / Unix {with examples}
  We use the df command to find total disk space and available space on a Linux / Unix file system. Let us see how to use the df command to view the amount of free space left on your Linux, macOS, *BSD and Unix file system. We will also explain how to automate disk space monitoring and send an email alert or push notification to your mobile device.
  
• How to upgrade ZFS storage pools version on FreeBSD
  When we update FreeBSD from 12 to 13, we get an updated version of ZFS. FreeBSD 13 released with OpenZFS support with various performance boosts. Sometimes OS patching and minor FreeBSD upgrade can also offer an updated zpool version. In any case, we need to upgrade the ZFS storage pools version to get newer functionality and bug fixes. This page explains how to update the ZFS storage pools version on FreeBSD.
  
• How to install lftp on FreeBSD using the CLI
  I need to download a large file and get the specified file using several connections to speed up downloads on FreeBSD. How do I install lftp and download files using FreeBSD?
  
• How to redirect standard (stderr) error in bash
  I am trying to redirect bash message into file named output.log. But, it is not getting redirected. How do I redirect both standard output and standard error in bash shell? In Linux, how do I redirect error messages?
  
• Stopping cron sending email alert for Linux/Unix jobs
  How do I to disable the email alert send by crontab? When my job is executed and the jobs cannot run normally it will sent an email to root. Why do I receive e-mails to my root account from cron? How can I prevent this?
  
• ls* Commands Are Even More Useful Than You May Have Thought
  Everything is a file under Linux and ls* and friends can help you to dig out more information from the system than you originally thought. These Linux tips may come in handy when you need to find out information quickly without going through /proc or sysfs.
  
• How to install X Window System XQuartz on macOS for ssh X11 forwarding
  Learn how to set up and use ssh based X11 forwarding on your macOS so that you can run graphical apps on your Mac from Linux or *BSD/Unix system.
  
• How to find Intel NUC (or any laptop/desktop) BIOS version and model name on Linux/BSD
  Simple bash for loop to display your Linux/*BSD system's OEM name, product version from the CLI using dmidecode.
  
• zcommands: Read gzip Compressed Text Files On a Fly on Linux and Unix
  Linux and Unix like operating systems comes with z* commands. These commands allow you to read gzip compressed text files using zless, zcat, zmore, and friends commands. The gzip command reduces the size of the files using Lempel-Ziv coding (LZ77). Whenever possible, each file is replaced by one with the extension .gz while keeping the same ownership modes, access, and modification times. z* commands have some cool usage too, such as display the current time in different zonename.
  
• How to remove grep command while grepping using ps command
  We all use ps and grep foo command combo to find and narrow down a running process on Linux and Unix-like systems. However, this results in an annoying problem where the grep command also appears in their own grepping result. Let us see how to exclude or hide grep from ps results.

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