nixCraft Linux & Unix Sysadmin/DevOps Tutorial Newsletter

[nixCraft]

Welcome to nixCraft Linux/Unix newsletter for Thursday, 14 January 2021. I hope you will enjoy this version of the newsletter.

• Top 6 awesome text editors for Linux and Unix command-line users/developers
  Let us see the top 6 text editors for Linux, macOS, and Unix command-line users/developers.
   
• bpytop – Awesome Linux, macOS and FreeBSD resource monitor
  The bashtop is an impressive Linux resource monitor that shows usage and stats for processor, memory, disks, and network. However, it suffers from bash itself, and cross-platform support is a nightmare. Now we have the Python port of bashtop. We can use a resource monitor that shows usage and stats for CPU, RAM, SSD (hard disk), network, and processes information in a lovely format.
   
• How to change LUKS disk encryption passphrase in Linux
  We use encryption to protect mobile devices. For instance, I always use LUKS disk encryption to protect all files stored on my SSD. Dm-crypt (Cryptsetup and LUKS) open-source disk encryption is transparent disk encryption and a great way to keep your data secure. However, changing passphrase is a bit of a challenge for new Linux users and developers. This step-by-step guide explains how to find LUKS slots assigned to you and change your passphrase.
   
• Significant vulnerabilities that crippled IT world this decade (2010-2020)
  The last ten years in the computer and IT security world are crippled with so many vulnerabilities. We saw massive cloud computing adoption and end-users using mobile devices with high speed 4G LTE networks. A threat actor may have exploited such weakness in modern computers and networks. Let us look into top vulnerabilities and the attack surface in this decade (2010-2020) that affected Linux/Unix, macOS, IT, cloud-computing, and computers in general.
   
• How to unlock LUKS using Dropbear SSH keys remotely in Linux
  On Linux, we encrypt our partitions and entire disk using Linux Unified Key Setup-on-disk-format (LUKS) for security and privacy reasons. We unlock LUKS protected disk by providing a passphrase at boot time. You need to be in front of your computer or use a remote console to open the encrypted disk under Linux at boot time. Let us see how to unlock LUKS using Dropbear SSH keys in Linux at boot time.
   
• How to rollback an apt-get upgrade if something goes wrong on Debian / Ubuntu Linux
  Rolling back to the previous version may solve the problem or free the disk space. Both CentOS/RHEL support rollback feature, but I learned hard way both Debian and Ubuntu does not support rollback feature yet.
   
• tuptime - Linux See Historical and Statistical Uptime of System
  Tuptime is a tool for report the historical and statistical real time of the system, keeping it between restarts. Like uptime command but with more interesting output. It works on both Linux and FreeBSD.
   
• Linux Run Command As Another User
  Tips on how to run Linux commands as another user or as the root user on your Linux server or desktop.
   
• How to install xfs and create xfs file system on Debian/Ubuntu Linux
  I recently switched to a Ubuntu/Debian Linux server from a CentOS/RHEL 7.x. How do I install xfs (mkfs.xfs command) on a Debian/Ubuntu Linux server? How do I create and manage file XFS file system on a Ubuntu or Debian Linux LTS server?
   
• Linux Set Environment Variable Command Tutorial
  How do I customize the shell environment variable under Linux operating systems? How can I set and view environment variable on Linux?
   
• curl hide progress bar output on Linux/Unix shell scripts
  How can I get curl command not to show the progress bar output? How can I hide curl command output? Is there is a simple way for silencing curl's progress output on an Ubuntu Linux desktop?
   
• How to scan port from your Linux, macOS, and FreeBSD Unix system using netcat/nc
  How do I find out which ports are opened on my own server? How do I run port scanning using the nc command instead of the nmap command on a Linux or Unix-like systems?
   
• How do I enable UFW in Ubuntu? Learn how to protect your box
  So how do you enable UFW in Ubuntu Linux 20.04 / 18.04 / 16.04 LTS server or desktop system to protect yourself from hackers and crackers? Let us see how easy it is to use ufw on Linux.
   
• How do I apply package updates to my Ubuntu system?
  Ubuntu Linux provides simple but easy to use GUI and CLI tools to apply package updates to your operating systems. Before installing an update, ensure all previously-released errata relevant to the laptop or desktop/server have been applied.
   
• How to declare Boolean variables in bash and use them in a shell script
  I need to define a bash variable called failed and set the value to False. When my script is called from a cron job, specific tasks might fail, and then I need to flip failed to True. Based upon $failed, I need to send an email alert that my cron job has failed. So how can I declare and use Boolean variables in a shell script running on a Linux server?
   
• How to configure Intel Wifi on Debian Linux when you get firmware: failed to load iwlwifi-8265-36.ucode error
  How do I load iwlwifi-8265-36 firmware and enable this driver card on Debian Linux version 10/11 and assign an IP address using DHCP?
   
• How to restart CentOS or RHEL server safely
  Is there is a safe reboot command that will do a graceful reboot for our CentOS or RHEL 7 server without causing any issues? What is the best way to appropriately restart CentOS/RHEL over ssh?

FreeBSD specific tutorials 

• How to write FreeBSD image to USB disk for installation using dd command
  This quick tutorial explains how to download and prepare the USB stick/pen drive to install FreeBSD 12.2 to install FreeBSD using the target computer’s USB port.
   
• How to set up FreeBSD 12 VNET jail with ZFS
  How do I install, set up and configure a FreeBSD 12 jail with VNET on ZFS? How can I create FreeBSD 12 VNET jail with /etc/jail.conf to run OpenVPN, Apache, Wireguard and other Internet-facing services securely on my BSD box?
   
• FreeBSD send e-mail with attachments from command line or shell prompt
  I need to send a few reports everyday as a mail attachment. I'm using FreeBSD 6.2/7.x/8.x/9.x/10.x/11.x/12.x or above server. How do I send mail from a command line or a shell script when using FreeBSD Unix server?
   
• How To Add, Delete, and Grant Sudo Privileges to Users on a FreeBSD Server
  I am setting up a new FreeBSD server. I do not want to use a default root user who has full system access. How can I setup and grant sudo privileges to users on a FreeBSD VPS or server? How do I create a sudo user on FreeBSD 11.x/12.x/13.x?
   
• FreeBSD find CPU (processor) temperature command
  I am a new FreeBSD Unix user. How do I get the temperature of an Intel or AMD processor (CPU) in FreeBSD using command line option? Is there a command line option for determining CPU temperature on FreeBSD Unix operating system version 9.x/10.x/11.x/12.x/13.x?

Until next time.

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