Unix Basics Quiz

Let us test your basic knowledge of Unix systems, including commands.

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Ansible zypper update all packages on OpenSUSE/SUSE

I got a cluster of servers powered by OpenSUSE / SUSE Enterprise Linux. How can I update all of them using the zypper module of Ansible? How can I use Ansible for system updates and reboot the server when kernel upgrades took place on SUSE/OpenSUSE?

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Make Linux/Unix Script Portable With #!/usr/bin/env As a Shebang

Why do some shell/perl/python scripts begin with #!/usr/bin/env? How do you make your Unix script portable across different UNIX like operating systems?

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CentOS 8 set up WireGuard VPN server

How do I install and set up WireGuard VPN server on a CentOS 8 Linux? How can I configure CentOS 8 as the WireGuard VPN server?

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CentOS 8 Set Up OpenVPN Server In 5 Minutes

How do I set up an OpenVPN Server on CentOS 8 Linux server to shield my browsing activity from bad guys on public Wi-Fi, and more?

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exa a modern replacement for ls command in rust for Linux/Unix

ls is a command to show files in Linux and Unix-like operating systems. A ls command first appeared in a version of AT&T UNIX UNIX as well as in Multics. BSD and GNU Coreutils package provides the ls command with minor syntax changes. There is now third alternative named exa. It is a modern replacement for ls command.

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Linux Trivia: Did you know what Linus wanted to call his kernel initially?

Linux Trivia: Linux very nearly wasn't called Linux. Did you know what Linus wanted to call his kernel initially?

1. Free Unix
2. Freax
3. LinusOS
4. TuxOS

Think you know the answer?

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20 Unix/Linux Command Line Tricks - Part I

{Updated} Unix and Linux command line tricks to increase productivity at the Terminal. I have found them over the years, and I am now going to share with you.

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Linux append text to end of file

{Updated} I am new Linux user and sysadmin for CentOS enterprise Linux 7 running on couple of VMs and bare metal boxes. How to add lines to end of file? How do I append text to end of file using the cli on Linux? What command I need to type to send the output of the command to end of file?

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Linux Quiz

Let us test your basic knowledge of Linux systems, including commands.

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Letsencrypt is revoking certificates on March 4

Let's Encrypt is a non-profit certificate authority that provides X.509 certificates for Transport Layer Security (TLS) encryption free of cost. The TLS certificate is valid for 90 days only. However, Due to the bug, they need to revoke many (read as "certain") Let’s Encrypt TLS/SSL certificates. Let us see how to find out if you are affected by this bug and how you can fix it to avoid any problems with your TLS/SSL certificates.

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How to append text to a file when using sudo command on Linux or Unix

I am trying to add entry to /etc/hosts file using 'sudo echo '192.168.1.254 router' >> /etc/hosts' command, but getting an error that read as, -bash: /etc/hosts: Permission denied. How do I insert or append text to a file when running sudo command on Linux or Unix-like system?

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How to enable firewalld logging for denied packets on Linux

How do I enable firewalld logging for denied packets on Linux operating systems so that I can view all dropped packets information? How can I view a log of the traffic blocked by FirewallD under a CentOS/RHEL (Red Hat Enterprise Linux)/Suse/OpenSUSE Linux?

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How to Set Up and Use LXD on CentOS 8.x / RHEL 8.x

LXD is a next generation system container manager. It offers a user experience similar to virtual machines but using Linux containers instead. It's image based with pre-made images available for a wide number of Linux distributions. How do I set up and install LXD on a CentOS 8.x or RHEL 8.x server?

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Vim show line numbers by default on Linux

How do I show line numbers in Vim by default on Linux?

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Append Current Date To Filename in Bash Shell

{Updated} How can I append a current date from a variable to a filename under Linux or Unix bash shell? How do I append date to filename?

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How to update/upgrade Pi-hole with an OpenVPN on Ubuntu/Debian Linux server

I installed an OpenVPN server with Pi-hole software to block block ads, reduced my 4G/3G/LTE traffic on the same Debian or Ubuntu Linux server. How do I upgrade my Pi-hole to the latest version using command line?

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Linux Kill and Logout Users Command

Show do you kill a Linux user login session? Yet another newbie question that suggests sysadmin/people love to kill and show their power to the rest of the world. There is a package called procps. It includes various useful and nifty utilities. One of such utility is skill which is responsible to send a signal to users and process.

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Linux bind IP that doesn’t exist with net.ipv4.ip_nonlocal_bind

How do I allow Linux processes to bind to IP address that doesn't exist yet on my Linux systems or server?

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Display Colored 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?

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Change my default shell in Linux using chsh

How do I change my default shell in Linux?

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Linux iptables delete prerouting rule command

I am a new Linux server sysadmin. I need to delete the PREROUTING rule. How do I delete the prerouting rule on Linux server?

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Linux List / Display and view all cron jobs

{Updated} How do I view currently setup or all running cron jobs under a Linux or Unix-like operating systems?

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How to Install phpredis on CentOS 8 / RHEL 8

How do I install PHP extension called phpredis (php-redis) for interfacing with Redis cluster on CentOS 8 or RHEL 8?

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Bash For Loop Examples

{Updated} Bash for loop is useful for automating repetitive tasks in IT or other stuff. Let us see how to use bash for loop to repeat specific tasks under Linux, *BSD, macOS, and Unix-like systems.

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How to use parallel ssh (PSSH) for executing commands in parallel on a number of Linux/Unix/BSD servers

Recently I come across a nice little nifty tool called parallel ssh (PSSH) to run a single command on multiple Linux / UNIX / BSD servers. You can easily increase your productive with this SSH IT automation tool.

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How to Undo in Vim / Vi text editor

How do I undo a recent change in the vim text editor?

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How to check Ubuntu version in Linux command line

I am a new Linux system user. How do I check Ubuntu version In Linux command line?

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CentOS SSH Installation And Configuration

How do I install and configure ssh server and client under CentOS Linux operating systems? Can you explains CentOS SSH installation commands?

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Shell Script Put Multiple Line Comments under Bash/KSH

How do I put multi line comment under a shell script? Can you tell method to set multiline shell script comments?

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Ubuntu Install Tinc and Set Up a Basic VPN

How do I install Tinc and Set Up a Basic VPN on Ubuntu Linux 18.04/20.04 LTS server?

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Debian Linux 10.3 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 10.2.

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System76 Announces AMD Threadripper Linux Workstations

System76 is a Denver, Colorado-based American computer manufacturer. They are specializing in the sale of Linux powered laptops, desktops, and servers. Last year System76 announced two Intel laptops with Coreboot, which as an alternative to proprietary BIOS using Intel 10th Gen CPUs. Now, System76 updated its Linux workstations line and ship with the latest AMD chips for CPU-intensive workloads. But how much of a difference can 64 cores AMD CPU make?

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Ansible apt update all packages on Ubuntu / Debian Linux

I have a bunch of servers powered by Ubuntu and Debian Linux. How do I update all of them using the apt module of Ansible? How can I use Ansible for system updates and reboot the box when kernel upgrades took place?

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Linux extend file system after resize disk volume

I increased the size of the volume in Linux using my cloud service providers' online tool. My original disk size was 200GB, and I grew to 400GB. However, I only able to use 200GB and not 400GB. How do I resizing my disk and extend the file system resizing a disk volume?

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Linux / Unix desktop fun: gti get jeep/car when you mistype git

One of the most common mistakes developers and ops people make is typing gti instead of git command. I set an alias i.e. alias gti=git, but then you may miss out on the jeep/car on your screen.

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Thinkpad update firmware on Linux (X1 extreme/P1 gen2)

I have ThinkPad P1 Gen 2 or X1 Extreme 2nd Laptop. Can I easily Install ThinkPad firmware updates on Linux using GUI?

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OpenSUSE install sudo to execute commands as root

There is no sudo installed by default on my OpenSUSE Linux server. Other users and I need to use 'su -' command to run commands as root. How do I install a sudo package on OpenSUSE Linux?

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Explain DEBIAN_FRONTEND apt-get variable for Ubuntu / Debian

Can you explain DEBIAN_FRONTEND apt or apt-get variable? How and why I need to use this in Docker or shell scripts under a Debian and Ubuntu Linux?

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Ubuntu 20.04 LTS change hostname permanently

I am a brand-new Ubuntu Linux 20.04 LTS VM user. By default, my server name to 'localhost' during cloud installation, but now I would like to change the computer name to 'ubuntu-2004-nixcraft'. Can you tell me how do I remove the localhost and set it to ubuntu-2004-nixcraft on Ubuntu 20.04 Linux? How do I change the Ubuntu computer name from 'localhost' to 'ubuntu-2004-nixcraft'? Can you tell me more about Ubuntu Linux change hostname command?

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Linux Rename Multiple Files At a Shell Prompt

How do I rename multiple files at a shell prompt under a Linux or UNIX operating systems?

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Upgrade Ubuntu 18.04 to 20.04 LTS using command line

I need to upgrade the Ubuntu Linux version 18.04 LTS server to a 20.04 LTS server using the command line option. How do I upgrade Ubuntu 18.04 to 20.04?

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Protects Linux machines from accidental shutdowns/reboots with molly-guard

Oops! I did it again. I thought I was logged into my home server. Turns out I rebooted the db server. Another my not so favorite is typing 'shutdown -h 0' into the wrong terminal. I know a few people who have admitted to doing that here.

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Linux find Windows 10 OEM product key command

I removed and installed Ubuntu Linux 16.04 LTS on my development Lenovo laptop. However, I need to use my Windows 10 pro in KVM VM for running the accounting app. How do I find and print my embedded Windows 10 pro key from a Linux command line option? How can I retrieve Microsoft Windows 8 and 10 OEM product key from BIOS?

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Linux / Unix Rsync Copy Hidden Dot Files and Directories Only

How do I use the rsync tool to copy only the hidden files and directory (such as ~/.ssh/, ~/.foo, and so on) from /home/jobs directory to the /mnt/usb directory under Unix like operating system?

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Add a new user account with admin access on Linux

How do I add a user account with admin (sudo) access on Ubuntu or CentOS Linux cloud server? How can I add a new user with admin account level access in Linux?

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Alarm clock Set Timeout For A Shell Command

How can I run a command called foo, and have it timeout/abort after 10 seconds under GNU/Linux running bash shell or script? How do I run the command under an alarm clock?

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How to use/run bash aliases over ssh based session

I have set up a bash alias named file_repl. It works entirely when I log in using ssh command. However, my bash aliases are not running over ssh, for example:
$ ssh vivek@server1.cyberciti.biz file_replbash: file_repl: command not foundHow do I run bash shell aliases when I use ssh command?

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CentOS Linux 8.1 (1911) released and here is how to upgrade it

CentOS Linux 8.1 (1191) released. It is a Linux distribution derived from RHEL (Red Hat Enterprise Linux) 8.1 source code. CentOS was created when Red Hat stopped providing RHEL free. CentOS 8.1 gives complete control of its open-source software packages and is fully customized for research needs or for running a high-performance website without the need for license fees. Let us see what's new in CentOS 8.1 (1911) and how to upgrade existing CentOS 8.0.1905 server to 8.1.1911 using the command line.

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Dell XPS 13 Developer Edition 2020 Ubuntu Laptop Announced

Look like Dell listing to customer feedback. Dell XPS 13 Developer Edition is the ultimate Linux laptop for developers and Linux enthusiasts/power users. The Dell XPS 13 Developer Edition 2020 now supports 10th Gen Intel CPU and 32GB ram. This system comes pre-installed with Ubuntu Linux 18.04, but you can install any other distro.

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