nixCraft Linux & Unix Sysadmin/DevOps Tutorial Newsletter

[nixCraft]

Welcome to nixCraft Linux/Unix newsletter for Monday, 08 March 2021. I hope you will enjoy this version of the newsletter.

• Linode cloud firewall: Do you need it to protect the Linux server?
  Linode is an original cloud platform and founded before AWS. Back then, we used to call them VPS (Virtual Private Server). Recently they added a new firewall feature to control network access to my Linode server from the Cloud. Let us test drive Linode cloud firewall.
   
• Adding spice to your sudo session with a lecture file on Linux or Unix
  Despite some severe bugs in sudo, it remains the defacto tool to gain root shell or run command as another user on Linux, macOS, and Unix-like systems. The sudo command allows the system administrator to grant an individual user access to unprivileged commands. For instance, I can give developers the ability to restart the Apache webserver or PHP/Python process on a Linux server. Let us see how to remind developers and unprivileged users about the power of sudo for fun and profit. In this quick tip, I will show you how to add some spice to your sudo session with a lecture file on Linux or Unix.
   
• How to install Dart on Linux and set up VIM as IDE
  Dart is easy to use BSD licensed programming language to build mobile, desktop, server, and web apps. Google creates and maintains the Dart ecosystem. It follows C-style syntax. We can compile code either to the native platform or JavaScript. Flutter allows building iOS/Android mobile and desktop/web apps from a single code base. Let us see how to install Dart programming language on a Debian or Ubuntu Linux and set vim as IDE.
   
• FreeBSD jail, xen, and .pam_login_access security fixes released
  All supported versions of FreeBSD are affected by various security bugs that need to be applied ASAP. If the process is privileged, it may escape jail and gain full access to the FreeBSD system. Similarly, when using Xen, a malicious or buggy frontend driver may be able to cause resource leaks. Let us see what and how to fix these security vulnerabilities on FreeBSD.
   
• 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. Let us see how to enable LUKS disk encryption with a key file.
   
• How to use the oathtool Linux command line for 2 step verification (2FA) code generation without any third-party apps
  I do not wish to use Google Authenticator or Authy app that generates 2 step verification (2FA) codes on my iOS/Android phone. Is there any way I can produce 2FA codes from Linux command line for popular sites such as Gmail, Twitter, Facebook, Amazon and more?
   
• Linux Filesystem Error: Transaction failed when using LXD
  I am a big fan of LXD, a next-generation Linux system container manager and default on Ubuntu. It allows me to run desktop apps or server apps in an isolated environment. Ubuntu provides LXD with robust security in mind. However, this might lead to undesired side effects, such as individual packages under OpenSUSE or CentOS Linux may not be updated. One such package is the filesystem package. Let us see how to fix Error: Transaction failed when you try to update filesystem package under CentOS, OpenSUSE, and other Linux containers running under LXD.
   
• How to find NetworkManager version on Linux
  How do I check or find NetworkManager version on Linux distribution?
   
• How to check if file does not exist in Bash
  How can I check if a file does not exist in a Bash script?
   
• How to check memory utilization in Linux
  How do I check memory utilization in Linux using command-line and GUI options?
   
• How to reset WordPress password using MySQL CLI
  So bizarrely, I forgot my WordPress admin password, including my login name. I did not add my login details to my password manager either. The container image that I built lacking outgoing email support (SMTP) too. I got stuck. Fortunately, I have full root access to my MySQL/MariaDB server hosted at AWS EC2, and here is how to reset a forgotten WordPress password using MySQL command-line.
   
• How to import WireGuard profile using nmcli on Linux
  I have multiple wireguard profiles on Linux. Is there any way to import WireGuard profile (/etc/wireguard/wg{0,1,2}.conf files) using nmcli on Linux? I don’t want to become root and run systemctl start wg-quick@wg0. How can I import an existing WireGuard profile from using NetworkManager command-line interface?
   
• How To - Linux List Disk Partitions Command
  How do I list all hard disk partitions under a Linux operating systems using the CLI and GUI tools?
   
• Bash Shell: Replace a String With Another String In All Files Using sed and Perl -pie Options
  How do I replace a string with another string in all files using sed, Bash or Perl?
   
• How do I install python an interactive high-level object-oriented language on Linux operating system?
  How To Install Python On Linux 2.x/3.x latest version
   
• How To Install EPEL Repo on an RHEL 8
  How do I install the extra repositories such as Fedora EPEL repo on an Red Hat Enterprise Linux server version 8?
   
• How to check boot path (partition) in Linux
  How do I identify the boot device or boot path in Linux operating system?
   
• Nginx: 413 - Request Entity Too Large Error and Solution
  I am getting 'Nginx 413 Request Entity Too Large' error. How do I fix this problem and allow image upload upto 2MB in size using nginx web-server working in reverse proxy or stand-alone mode on Unix like operating systems?
   
• How To Use chmod and chown Command in Linux
  This page explains how to use chmod and chown command on Linux or Unix-like systems.
   
• Python For Loop Examples
  How and when do I use for loops under Python programming language? How can I use the break and continue statements to alter the flow of a Python loop?
   
• How to set up WireGuard VPN server on Ubuntu 20.04
  This page explains how to install and set up WireGuard VPN on Ubuntu 20.04 LTS Linux server.
   
• How To Update Fedora Linux using terminal for latest software patches
  I recently switched from Windows server to Fedora 32/33 server running in the cloud. How do I apply software updates and patches on Fedora 32/33 server using the terminal application?