nixCraft Linux & Unix Sysadmin/DevOps Tutorial Newsletter

[nixCraft]

Welcome to nixCraft Linux/Unix newsletter for Tuesday, 06 April 2021. I hope you will enjoy this version of the newsletter.

• Download of the day: AlmaLinux DVD/CD ISO {trending}
  AlmaLinux is the first significant replacement for CentOS Linux 8. As you know, CentOS 8 Linux, as a rebuild of RHEL 8, will end in 2021. AlmaLinux is a free and open-source RHEL 8 fork built by the team at CloudLinux, inspired by the community. Let us take a quick look at AlmaLinux 8 and how to download AlmaLinux DVD/CD ISO on your system.
   
• cpufetch – awesome CPU architecture info tool for Linux and macOS {trending}
  Typically we use the lscpu command or /proc/cpuinfo command on Linux to check CPU information. I recently found another simplistic yet fancier CPU architecture fetching tool inspired by neofetch, pfetch or screenfetch. Let us see how to install cpufetch on Linux, macOS, Android, and Windows to fetch CPU details.
   
• How to install ncdu on Linux / Unix to see disk usage {trending}
  The du (disk usage) command summarizes directory trees’ sizes, including all of their contents and individual files’ sizes on Linux and Unix-like systems such as macOS. It helps track down space hogs. In other words, we can list directories and files that consume large amounts of space on a hard disk drive. Let us see the ncdu command, a curses-based version of the well-known du command.
   
• Interview with Abhinav Upadhyay, NetBSD contributor and machine learning software developer
  Abhinav Upadhyay is an Indian software developer, the NetBSD project contributor, and works with the exciting field of machine learning (ML). Recently I did a quick Q and A with Abhinav about his life-changing journey with NetBSD, getting started with ML and FLOSS community, and his daily workflow.
   
• Debian Linux 10.9 released and here is how to upgrade it
  The Debian GNU/Linux project has released an updated version of its stable Linux distribution Debian 10 (“buster”). You must upgrade to get corrections for security problem as this version made a few adjustments for the severe issue found in Debian version 10.8. Debian is a Unix-like (Linux distro) operating system and a distribution of Free Software. It is mainly maintained and updated through the work of many users who volunteer their time and effort. The Debian Project was first announced in 1993 by Ian Murdock.
   
• Interview with curl creator and Swedish software developer Daniel Stenberg
  Even if you do not use the curl command daily, the chances are high that you are still using curl and don’t know. IoT and tons of other services on the Internet depend upon libcurl for network operations. Daniel Stenberg is a Swedish software developer, recipient of the Polhem Prize 2017, on cURL. Recently I did a quick Q and A with Daniel about starting the curl project and his daily workflow.
   
• How to enable LUKS disk encryption with keyfile on Linux
  We can easily add a key file to LUKS disk encryption on Linux when running the cryptsetup command. A key file is used as the passphrase to unlock an encrypted volume. The passphrase allows Linux users to open encrypted disks utilizing a keyboard or over an ssh-based session. There are different types of key files we can add and enable LUKS disk encryption on Linux as per our needs
   
• How to configure static IP address on Alpine Linux
  At home or in a cloud environment, IP addresses are assigned dynamically by the DHCP server. Setting a static IP address on your Alpine Linux server is required for various reasons. For instance, Alpine Linux is configured as a DHCP server or KVM server to host multiple VMs. Static IP address makes it easy to work with port forwarding, firewalling, and HTTPS server too. This quick tutorial will explain how to set up a static IP address on Alpine Linux.
   
• How To View CPU Temperature On Alpine Linux
  Alpine Linux comes with a monitoring sensors package called lm-sensors. It is an easy-to-use and open-source application for monitoring CPU temperatures, voltage, and fans. This page explains how to install, configure, and use lm-sensors on Alpine Linux to view CPU temperature and other data on your Alpine Linux-powered laptop or server.
   
• How to restart systemd without rebooting Linux when critical libraries installed {trending}
  Whenever we update a critical library such as OpenSSL, we need to restart any daemons that use the library. Systemd with PID 1 itself also uses OpenSSL. How do you restart the systemd daemon without rebooting Linux and other services such as Nginx, SSHD, Firewalld? Here are some tips.
   
• How to install vnstat on Alpine Linux
  VnStat is a free and open-source app for servers and routers. It is a console-based network traffic monitor. It keeps a log of the 5-minute interval, hourly, daily, monthly, and yearly network traffic for the selected interface(s). Let us see how to install vnStat on the Alpine Linux server to keep a tab on bandwidth usage.
   
• How to install curl on Alpine Linux
  Curl is URL retrieval (download/upload) command-line utility and library. It is free software for Alpine Linux. This page explains how to search and install curl on Alpine Linux using the apk command.
   
• How to send emails with Postfix and Amazon AWS SES on RHEL/CentOS 8
  Amazon Simple Email Service (SES) is a hosted cloud-based email service to send and receive email using your email addresses and domains. Typically SES is used for sending bulk email or routing emails without hosting MTA. One can use the CLI or server-side programming languages such as PHP or Python to transfer an email via SES. This quick tutorial will show you how to route all outgoing emails with Postfix and Amazon AWS SES on Red Hat Enterprise Linux (RHEL) or CentOS version 8.
   
• How to enable automatic updates for RHEL/CentOS 8 {trending}
  I talked about yum-cron that provides auto yum updates nightly via cron. However, this package is no longer available on CentOS/RHEL 8 or Fedora Linux 29 or above. So how do you enable and install updates atomically on a CentOS/RHEL version 8.x? They have a new package called dnf-automatic. This page explains how to install and then enable dnf-automatic to install updates for you in the background.
   
• 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?
   
• How to Find if Linux is Running on 32-bit or 64-bit CPU {trending}
  I am a new Linux system user. How do I determine if my CPU is 64bit or not on a Linux operating systems using command line option? How can I check Linux kernel is in 32 bit or 64 bit mode?
   
• pinfo - Read Linux Info Documentation in Colors
  You can display man pages in colors under Linux and Unix-like systems. Similarly, you can display info pages in colors.
   
• How to find largest file in directory recursively using find/du under Linux {trending}
  I have 500GB SSD installed on my Linux server. My web server is running out of the disk space. I need to find a biggest or largest file concerning file size on the disk. How do I find largest file in a directory recursively using the find command?
   
• How to create MySQL admin user (superuser) account
  Explains 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 use scp/rsync to copy file with a colon (:) in it
  How do I copy file with scp or rsync with a colon in it?
   
• Bash Read Comma Separated CSV File on Linux / Unix
  How do I read comma separated CVS file under UNIX / Linux / BSD / MacOS bash script?
   
• How to configure and install WiFi driver for Broadcom b43 BCM43228 on Fedora Linux
  This page explains how to enable and install Broadcom b43 driver under a Fedora Linux v29/30/31/32/33/34. The driver (broadcom-wl and kmod-wl) works with the many Wireless chipsets from Broadcom.
   
• Bash get exit code of command on a Linux / Unix
  I am a new Linux system user. How do I get the exit code of a command? How do I get the exit code or status of Linux or Unix shell command and store it into a shell variable?
   
• 25 Iptables Netfilter Firewall Examples For Linux {trending}
  Linux comes with a host based firewall called Netfilter. The netfilter is a set of hooks inside the Linux kernel that allows kernel modules to register callback functions with the network stack. A registered callback function is then called back for every packet that traverses the respective hook within the network stack. This Linux based firewall is controlled by the program called iptables to handles filtering for IPv4, and ip6tables handles filtering for IPv6. I strongly recommend that you first read our quick tutorial that explains how to configure a host-based firewall called Netfilter (iptables) under CentOS / RHEL / Fedora / Redhat Enterprise Linux. If you are using Ubuntu/Debian Linux, see how to setup UFW for more info. This post lists most simple iptables solutions required by a new Linux user to secure his or her Linux operating system from intruders.
   
• How To Display Color Man Pages in Linux and Unix
  How do I add a bit of color to my man pages under Linux / FreeBSD / Apple OS X / Unix like operating systems? How can I view colored man pages in Linux?
   
• How to test the network speed/throughput between two Linux servers {trending}
  I have setup total four servers in cloud based data center. They run either CentOS or Ubuntu Linux. I need to make sure clustered file system performance is reasonable as my servers shared with other users. How do I check the speed between the two Linux servers using command line options for private LAN/VLAN?
   
• Linux Add User To Group Using Command-Line 
  How can I add a user to a group under Linux operating system using command line options? How to add an existing user into a group in Linux using command-line options?