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Install Gitlab on CentOS 8 - Step by Step Process ?

This article covers how  to setup Gitlab on CentOS Linux.

Gitlab is an application tool that is used for source code management. It allows you to plan your development process; code, and verify; package software, and release it with an in-built continuous delivery feature; automate configurations management, and monitor software performance.


To be able to access the GitLab interface you'll need to open ports 80 and 443. 

To do so run the following commands:

$ sudo firewall-cmd --permanent --zone=public --add-service=http
$ sudo firewall-cmd --permanent --zone=public --add-service=https
$ sudo firewall-cmd --reload



To install Postfix service to send notification emails, and enable it to start at system boot, then check if it is up and running using following commands:

# yum install postfix
# systemctl start postfix
# systemctl enable postfix
# systemctl status postfix

Hide Files Inside Images in Ubuntu Using Steganography - Steps to do it ?

This article covers how to hide files inside images through four different methods including both the command line and the graphical methods. 

You can simply embed the confidential data, along with a password or passkey so that only a trusted person can open that file. 

This type of encryption where you hide one file securely into another is called Steganography.


How to install Steghide utility via command line on Ubuntu ?

1. To install the latest version of this tool, open the Ubuntu Terminal and first update your repository index through the following command as sudo:

$ sudo apt update

2. Now install the steghide utility through the following command:

$ sudo apt-get install steghide


To Remove / Uninstall Steghide tool from Debian:

Whenever you want to uninstall the Steghide tool from your system, simply enter the following command as sudo:

$ sudo apt-get remove steghide

Install YakYak on Ubuntu 20.04 - Step by Step Process ?

This article covers how to install Google Hangouts on the Ubuntu 20.04 system. Users can use YakYak to install the Google Hangouts application on their Linux systems. Basically, go through this guide to install YakYak on your Linux System.

YakYak is a free, open-source Google Hangouts client that works on Windows, macOS and (hurrah) Linux desktops.


To Install yakyak – Google Hangouts on Ubuntu / Debian:

1. Download and install the downloaded package.

$ sudo apt update
$ sudo apt-get -y install wget
$ wget https://github.com/yakyak/yakyak/releases/download/v${VER}/yakyak-${VER}-linux-amd64.deb

2. If you're running a 32-bit system, download.

$ wget https://github.com/yakyak/yakyak/releases/download/v${VER}/yakyak-${VER}-linux-i386.deb

3. Install the package using dpkg command line tool.

$ sudo dpkg -i yakyak-${VER}-linux-amd64.deb

or

$ sudo dpkg -i yakyak-${VER}-linux-i386.deb


To Install yakyak – Google Hangouts on CentOS / Fedora / RHEL:

1. For RHEL family line of distributions, you need to download and install from an rpm package.

$ sudo yum -y install wget
$ wget https://github.com/yakyak/yakyak/releases/download/v${VER}/yakyak-${VER}-linux-x86_64.rpm

2. For 32-bit system, get,

$ wget https://github.com/yakyak/yakyak/releases/download/v${VER}/yakyak-${VER}-linux-i386.rpm

3. After the download, install the package using rpm -Uvh

$ sudo rpm -ivh yakyak-${VER}-linux-x86_64.rpm

or for 32-bit:

$ sudo rpm -ivh yakyak-${VER}-linux-i386.rpm

Install Nmap on Ubuntu 20.04 - Step by Step Process ?

This article covers different methods to install Nmap on Ubuntu. If you want to learn how to use nmap, visit our guide on 15 Mostly Used Nmap Commands for Scanning Remote Hosts .

Nmap works by sending data packets on a specific target (by IP) and by interpreting the incoming packets to determine what posts are open/closed, what services are running on the scanned system, whether firewalls or filters are set up and enabled, and finally what operating system is running.


To install Nmap on Ubuntu:

1. Make sure the software packages on your Ubuntu system are up-to-date with the command:

$ sudo apt-get update

2. To install NMAP on Ubuntu, run the command:

$ sudo apt-get install nmap

The system prompts you to confirm and continue by typing y and pressing Enter.

3. To verify the installation was successful and to determine the current version of Nmap:

$ nmap --version

Wall Command in Linux with Examples - Learn Now

This article covers how Wall command works in Linux. Wall is a handy utility that helps a multi-user system admin to quickly notify other users to save their work before a system shutdown or reboots. 

Here, you will see some examples of how to use the wall command to communicate with logged-in users.

There are times when multiple users are logged in to a server computer, and you - the system/network admin - need to, say, restart the server to perform some maintenance task. 

Of course, the correct way is to inform all those who are logged in about the maintenance activity.

In Linux, there is a built in command line utility for this purpose called Wall.


What is wall command in Linux ?

As already mentioned, the wall command is used to send a message to all logged in users. 

It's syntax is:

$ wall [-n] [-t TIMEOUT] [file]


How to use wall command?

Basic usage is very straight forward - just execute the 'wall' command and write the message you want to transmit on the standard input. 

Once done, use the Ctrl+D key combination to signal the command that you're done writing the message: 

$ wall


How to remove header from broadcasted message?

In case you want to remove the header that appears with the broadcasted messages, you can do that using the -n command line option:

$ wall -n

Undo the Last Commit in Git - Step by Step Process ?

This article covers how to use the git reset command to undo the last commit in Git. 


To Undo the Last Commit:

The "reset" command is your best friend:

$ git reset --soft HEAD~1

Reset will rewind your current HEAD branch to the specified revision. Here, our goal is to return to the one before the current revision - effectively making our last commit undone.


To Undo Last Commit with revert:

In order to revert the last Git commit, use the "git revert" and specify the commit to be reverted which is "HEAD" for the last commit of your history.

$ git revert HEAD

The "git revert" command is slightly different from the "git reset" command because it will record a new commit with the changes introduced by reverting the last commit.

As a consequence, you will have to commit the changes again for the files to be reverted and for the commit to be undone.

Zoom Video Filters not Available in Linux ?

This article covers methods to fix Zoom Video Filters not Available in Linux.

Zoom Video Filters turned ON but no filters available

just close zoom and login when you reopen it. problem solved.

You need to sign up for a free account on Zoom to use video filters.


How to get video filters on Zoom?

Here are the steps to add video filters on Zoom:

1. Click on your profile picture which can be found in the top-right corner of the screen.

2. Click on the 'Settings' option from the dropdown menu.

3. From the Settings menu, click on the 'Video' tab which is the second option.

4. Here, you need to look for an option labelled 'Touch up my appearance'. You need to enable this feature by checking the box besides the option.


How to resolve Zoom video filters not showing ?

Several users on social media have been reporting that they are unable to view the Zoom filters on their computer. 

If you are one of the users facing this issue, you should note that you may not be able to see the filter if you are accessing the service using a web browser. 

You will need to install the latest version of Zoom desktop client on your system and sign in to view the filters.

Reset MySQL Root Password on Red Hat Enterprise Linux 8 - Step by Step Process ?

This article covers how to reset or change your MySQL root password on Red Hat Enterprise Linux 8.

MySQL is an open source relational database management system (RDBMS) with a client-server model for creating and managing databases based on a relational model.


To Reset the MySQL root password:

You must run the commands in the following steps as the root user. 

Therefore, you can either log in directly as the root user (which is not recommended for security reasons), or use the su or sudo commands to run the commands as the root user.

To reset the root password for MySQL, follow these steps:

1. Log in to your account using SSH.

2. Stop the MySQL server using the appropriate command for your Linux distribution:

For CentOS and Fedora, type:

$ service mysqld stop

For Debian and Ubuntu, type:

$ service mysql stop

3. Restart the MySQL server with the —skip-grant-tables option. To do this, type the following command:

$ mysqld_safe --skip-grant-tables &

4. Log into MySQL using the following command:

$ mysql

5. At the mysql> prompt, reset the password. To do this, type the following command, replacing new-password with the new root password:

UPDATE mysql.user SET Password=PASSWORD('new-password') WHERE User='root';

6. At the mysql> prompt, type the following commands:

FLUSH PRIVILEGES;
exit;

7. Stop the MySQL server using the following command.

You will be prompted to enter the new MySQL root password before the MySQL server shuts down:

$ mysqladmin -u root -p shutdown

8. Start the MySQL server normally. To do this, type the appropriate command for your Linux distribution:

For CentOS and Fedora, type:

$ service mysqld start

For Debian and Ubuntu, type:

$ service mysql start

Install FileZilla on Ubuntu 20.04 LTS - Step by Step Process ?

This article covers how to install FileZilla on Ubuntu 20.04 LTS system. Also we mentioned the steps to remove FileZilla in case you need to so.

FileZilla is a ftp client for both windows & linux operating system. It is a powerful client for plain FTP, FTP over SSL/TLS (FTPS) and the SSH File Transfer Protocol (SFTP). 


To Install FileZilla from command line on Ubuntu / Debian:

Use the following commands.

$sudo apt-get update
$sudo apt-get install filezilla

First command synchronizes the configured repositories.

This command is used to ensure that always the latest version of the software is installed.

Install Netdata Monitoring Tool on Ubuntu 20.04 - Step by Step Process ?

This article covers how to install and configure Netdata on Ubuntu 20.04 LTS and different metrics visualized in it. Netdata provides an excellent solution for monitoring your single node in real-time. You can configure alarms and notifications which can be triggered when a certain event or threshold is exceeded.


To install Netdata on Ubuntu:

1. You can install netdata on Ubuntu by running the following commands.

$ sudo apt update 
$ sudo apt install netdata 

Press 'y' if confirmation prompted by the installer.

2. Edit netdata configuration file in your favorite text editor.

$ sudo vim /etc/netdata/netdata.conf 

3. After modifying its configuration file, you can Save your file and restart netdata service:

$ sudo systemctl restart netdata 

Install VMware Workstation Player on Ubuntu 20.04 - Step by Step Process ?

This article covers how to install VMware Workstation on your instance of Ubuntu 20.04. With a virtual machine application like VMware, you can run another operating system inside your current operating system.


To Install VMware in Ubuntu:

1. Install required build packages

Open a terminal (Ctrl+Alt+T) and use the command below to install required build packages and Linux Kernel headers:

$ sudo apt install build-essential

2. Download VMware Workstation Player

Next step is to download the VMware Workstation Player from their website.

https://www.vmware.com/products/workstation-player.html

3. Install VMware Player

4. Use the command below to make the file executable:

$ chmod +x ~/Downloads/VMware-Player*

5. And then run the installation file:

$ sudo ~/Downloads/VMware-Player*

This will open an installation window.


To Uninstall VMware Player from Ubuntu:

If, for some reasons, you want to uninstall VMware Player, use the following command:

$ sudo /usr/bin/vmware-installer -u vmware-player

Press "Enter" and VMware Player will be removed from your system.

Sort command in Ubuntu Linux with examples

This article covers the basic syntax and usage of the sort command in Ubuntu Linux. To view help and learn about more sort options, visit the sort man page  or type sort –help in Terminal.

sort is a simple and very useful command which will rearrange the lines in a text file so that they are sorted, numerically and alphabetically. 


By default, the rules for sorting are:

1. Lines starting with a number will appear before lines starting with a letter.

2. Lines starting with a letter that appears earlier in the alphabet will appear before lines starting with a letter that appears later in the alphabet.

3. Lines starting with a lowercase letter will appear before lines starting with the same letter in uppercase.

An Introduction to Python Async IO

This article covers an Overview of Async IO in Python. Python 3's asyncio module provides fundamental tools for implementing asynchronous I/O in Python. It was introduced in Python 3.4, and with each subsequent minor release, the module has evolved significantly.

Asyncio is the standard library package with Python that aims to help you write asynchronous code by giving you an easy way to write, execute, and structure your coroutines. 

The Asyncio library is for concurrency, which is not to be confused with parallelism.


Concurrency does not mean Parallelism and vice-versa.

We can combine them both. 

We can have multiple threads, running Tasks parallely but each thread may not be running Tasks concurrently. 


Note:

1. Asynchronous IO (async IO): a language-agnostic paradigm (model) that has implementations across a host of programming languages.

2. async/await: two new Python keywords that are used to define coroutines.

3. asyncio: the Python package that provides a foundation and API for running and managing coroutines.

Install Docker in Ubuntu 20.04 and Run Nginx Container - Step by Step Process ?

This article covers how to install docker, pull docker images from docker hub and run an application in a container. Also, you will learn how to create persistent data storage and map with docker containers.

The open-source Docker platform contains a docker engine, a runtime environment that is used to execute, builds, and orchestrates containers. 


Facts about Docker Compose configurations file:

1. version: Compose file version which is compatible with the Docker Engine. You can check compatibility here.

2. image: We use latest Nginx and Certbot images available in Docker hub.

volumes:

3. public: we have configured this directory to be synced with the directory we wish to use as the web root inside the container.

4. conf.d: here we will place the Nginx configuration file to be synced with the default Nginx conf.d folder inside the container.

5. certbot/conf: this is where we will receive the SSL certificate and this will be synced with the folder we wish to inside the container.

6. ports: configure the container to listen upon the listed ports.

7. command: the command used to receive the SSL certificate.


To Start Docker Containers:

You need to pass the -d flag which starts the container in background and leaves them running.

$ docker-compose up -d

Install MySQL Version 8 on Red Hat Enterprise Linux 8 - Step by Step Process ?

This article covers how to Install MySQL Version 8 on Red Hat Enterprise Linux 8. Now, you should now have a fully functioning MySQL server version 8 running on your Server.


To Install MySQL 8.0 On CentOS 8 / RHEL 8:

1. Install MySQL 8.0 from MySQL Dev Community

Add the official repository of MySQL to install the MySQL community server:

$ rpm -ivh https://dev.mysql.com/get/mysql80-community-release-el8-1.noarch.rpm

Make sure the MySQL repository has been added and enabled by using the following command:

$ yum repolist all | grep mysql | grep enabled


To Manage MySQL server Service on Linux:

1. After the installation of MySQL, start MySQL server service using the following command:

$ systemctl start mysqld

2. The below command will Enable MySQL server at system startup:

$ systemctl enable mysqld

3. Verify that MySQL server is started using the following command:

$ systemctl status mysqld

Install FileZilla on Debian 10 - Step by Step process ?

This article covers the installation of FileZilla on Debian 10. FileZilla is a powerful open-source FTP client that comes in handy when you simply want to access your FTP server and manage files.


To install FileZilla on Debian Linux System:

1. Login to the Debian 10 system and run below apt command to update package index:

$ sudo apt update

2. Install FileZilla using command-line, run following apt command:

$ sudo apt install -y filezilla

3. Once FileZilla and its dependencies are installed successfully, run below command to verify the FileZilla version:

$ filezilla --version

15 Key Nmap Commands for Scanning Remote Hosts - Check them out now ?

This article covers Nmap commands that you can use to get started with scanning your remote hosts. There are hundreds upon hundreds of Nmap commands and Nmap scripts  that are used for scanning hosts and probing for any vulnerabilities.

Nmap, or Network Mapper, is an open source Linux command line tool for network exploration and security auditing. With Nmap, server administrators can quickly reveal hosts and services, search for security issues, and scan for open ports.

The Nmap tool can audit and discover local and remote open ports, as well as network information and hosts.

With the right Nmap commands, you can quickly find out information about ports, routes, and firewalls.

Install Skype on Debian 10 - Step by Step Process ?

This article covers how to easily install Skype on Debian 10. Skype is one of the most popular communication applications in the world.

It allows you to make free online audio and video calls and affordable international calling to mobiles and landlines worldwide.


To Skype on Debian Linux System:

Perform the following steps as root or user with sudo privileges to install Skype on your Debian Buster:

1. Open your terminal and enter the following wget command to download the latest Skype deb package:

$ wget https://go.skype.com/skypeforlinux-64.deb

2. Once the download is complete, install Skype by typing:

$ sudo apt install ./skypeforlinux-64.deb

That's it. Skype has been installed on your Debian desktop, and you can start using it.

Add User to Group in Ubuntu Linux - Step by Step Process ?

This article covers how to add a user to a group on Ubuntu Linux System. If you want to learn about adding or removing a user on Linux OS, you can follow our guide on How to Add and Remove Users on Linux .

User accounts can be assigned to one or more groups on Linux. You can configure file permissions and other privileges by group. For example, on Ubuntu, only users in the sudo group can use the sudo command to gain elevated permissions.


To Add a New Group on Ubuntu Linux:

If you want to create a new group on your system, use the groupadd command following command, replacing new_group with the name of the group you want to create:

$ sudo groupadd mynewgroup


To Add an Existing User Account to a Group:

To add an existing user account to a group on your system, use the usermod command, replacing examplegroup with the name of the group you want to add the user to andexampleusername  with the name of the user you want to add:

$ usermod -a -G examplegroup exampleusername

Create SFTP User with Specified Directory Permissions in Ubuntu 20.04 - Step by Step Process ?

This article covers steps to setup and new SFTP server by making the ssh configuration changes, adding new users, and assigning the required directory permissions. You can add as many users as you want or simply create a new group and make new users part of that group.

FTP is a great protocol for accessing and transferring files, but it has the shortcoming of being a clear text protocol. 

In other words, it's not secure to use over an internet connection, since your credentials and data are transmitted without encryption. 

The 'S' in SFTP stands for 'Secure' and tunnels the FTP protocol through SSH, providing the encryption needed to establish a secure connection.


To Configure SSH daemon on Ubuntu:

1. SFTP requires SSH, so if SSH server is not already installed on your system, install it with the following command:

$ sudo apt install ssh

2. Once SSH is installed, we need to make some changes to the SSHD configuration file. Use nano or your favorite text editor to open it:

$ sudo nano /etc/ssh/sshd_config

3. Scroll to the bottom of the file and add the following 5 lines at the very end and save file:

Match group sftp
ChrootDirectory /home
X11Forwarding no
AllowTcpForwarding no
ForceCommand internal-sftp

4. Restart the SSH service for these new changes to take effect:

$ sudo systemctl restart ssh

Manage Firewall Rules with UFW on Red Hat Enterprise Linux 8

This article covers how to secure Red Hat Enterprise Linux 8 with UFW. UFW may not be intended to provide complete firewall functionality, but it does provide an easy way to create and manage simple firewall rules.

A firewall is a way to protect machines from any unwanted traffic from outside. 

It enables users to control incoming network traffic on host machines by defining a set of firewall rules. 

These rules are used to sort the incoming traffic and either block it or allow through.

Note that firewalld with nftables backend does not support passing custom nftables rules to firewalld, using the --direct option.


How to start, stop, restart firewalld service on an RHEL 8?

By now you know about firewalld zones, services, and how to view the defaults. It is time to activate and configure our firewall.

1. Start and enable firewalld

$ sudo systemctl start firewalld
$ sudo systemctl enable firewalld

2. Stop and disable firewalld

$ sudo systemctl stop firewalld
$ sudo systemctl disable firewalld

3. Check the firewalld status

$ sudo firewall-cmd --state

4. Command to reload a firewalld configuration when you make change to rules

$ sudo firewall-cmd --reload

5. Get the status of the firewalld service

$ sudo systemctl status firewalld


When to use firewalld, nftables, or iptables:

1. firewalld: Use the firewalld utility for simple firewall use cases. The utility is easy to use and covers the typical use cases for these scenarios.

2. nftables: Use the nftables utility to set up complex and performance critical firewalls, such as for a whole network.

3. iptables: The iptables utility on Red Hat Enterprise Linux 8 uses the nf_tables kernel API instead of the legacy back end. 

The nf_tables API provides backward compatibility so that scripts that use iptables commands still work on Red Hat Enterprise Linux 8. For new firewall scripts, Red Hat recommends to use nftables.

Backup and Restore MySQL Databases on Red Hat Enterprise Linux 8 - Step by Step Process ?

This article covers how to take Backups and restore a MySQL database on Red Hat Enterprise Linux 8.


Advantage of logical backup:

The main advantage of logical backup over physical backup is portability and flexibility. 

The data can be restored on other hardware configurations, MariaDB versions or Database Management System (DBMS), which is not possible with physical backups.

Note that physical backup must be performed when the mariadb.service is not running or all tables in the database are locked to prevent changes during the backup.


The mysqldump client is a backup utility, which can can be used to dump a database or a collection of databases for the purpose of a backup or transfer to another database server. 

The output of mysqldump typically consists of SQL statements to re-create the server table structure, populate it with data, or both. 

Alternatively, mysqldump can also generate files in other formats, including CSV or other delimited text formats, and XML.


Advantages of Physical backup:

1. Output is more compact.

2. Backup is smaller in size.

3. Backup and restore are faster.

4. Backup includes log and configuration files.


You can use one of the following MariaDB backup approaches to back up data from a MariaDB database:

1. Logical backup with mysqldump

2. Physical online backup using the Mariabackup tool

3. File system backup

4. Replication as a backup solution


To Backing up an entire database with mysqldump:

Execute the command:

# mysqldump [options] db_name > backup-file.sql


Using mysqldump to back up a set of tables from one database:

To back up a subset of tables from one database, add a list of the chosen tables at the end of the mysqldump command:

# mysqldump [options] db_name [tbl_name …​]



To restore the data while keeping the original backup files, use the following procedure:

1. Run the mariabackup command with the --copy-back option:

$ mariabackup --copy-back --target-dir=/var/mariadb/backup/

2. Fix the file permissions.

When restoring a database, Mariabackup preserves the file and directory privileges of the backup. However, Mariabackup writes the files to disk as the user and group restoring the database. 

For example, to recursively change ownership of the files to the mysql user and group:

# chown -R mysql:mysql /var/lib/mysql/

3. Start the mariadb service:

# systemctl start mariadb.service

Install Apache Maven on Ubuntu 20.04 - Step by Step process ?

This article covers methods to easily install Apache Maven on the Ubuntu system. You will also learn how to uninstall Apache Maven from Ubuntu if you ever need to do so.

Apache Maven is a free and open-source project management tool primarily for Java projects. It is based on POM and also used to build and manage projects written in C#, Ruby, Scala, and others.


To Install Apache Maven on Ubuntu:

1. Apache Maven is based on Java. So Java must be installed in your server. You can install the Java using the following command:

$ apt-get install default-jdk -y

2. By default, Apache Maven is available in the Ubuntu 20.04 default repository. You can install it with the following command:

$ apt-get install maven -y

3. Once the installation is completed, you can verify the Apache Maven version with the following command:

$ mvn -version

Install LibreOffice on CentOS 8 - Step by Step Process ?

This article covers LibreOffice installation on CentOS 8 distribution. LibreOffice is a powerful and open-source office suite that can be used on Linux, Mac as well as on Windows.

It provides various features such as word documentation, spreadsheets, data processing, drawing, presentation design, Math calculation, and more.


How to uninstall Old LibreOffice or OpenOffice Versions ?

If any previously installed LibreOffice or OpenOffice versions you have, remove it using following command.

# yum remove openoffice* libreoffice* [on RedHat based Systems]
$ sudo apt-get remove openoffice* libreoffice*	[On Debian based Systems]

Install and Use Flatpak on Ubuntu 20.04 - Step by Step Process ?

This article covers the different commands for Flatpak installation on Ubuntu 20.04 system. Here, you will learn how you can install an application through Flatpak software. Also you will see the two different removal processes of Flatpak. 

Flatpak is a universal package system for software deployments, application virtualization, and most importantly package management that works on all Linux distros.

With a Flatpak package, you don’t need to worry about any dependencies and libraries as everything is already bundled within the application itself.


To Install Flatpak through Ubuntu Official Repository:

1. Update your system's repository index through the following command:

$ sudo apt-get update

2. Now you are ready to install Flatpak; you can do so by running the following command as sudo:

$ sudo apt-get install flatpak

3. You can check the version number of the application, and also verify that it is indeed installed on your system, through the following command:

$ flatpak --version


To Install Flatpak on OpenSUSE.

To enable Flatpak on OpenSUSE invoke the command:

$ sudo zypper install flatpak


To Install Flatpak on ArchLinux / Manjaro.

Finally, to enable Flatpak on Arch Linux and its flavors, invoke the command:

$ sudo pacman -S flatpak


How to remove Flatpak from Ubuntu?

This was all you needed to know about Flatpak. If you want, you can remove it through the following commands:

$ sudo apt-get remove flatpak

If you have installed the package from the PPA, you can remove the PPA through the following command:

$ sudo rm /etc/apt/sources.list.d/alexlarsson-ubuntu-flatpak-bionic.list

Install Atom Text Editor on Debian 10 - Step by Step Process ?

This article covers how to install Atom text editor on the Debian system. Atom is a very powerful text editor.

The Atom user interface is very clean and it has support for many important features such as split view, Git integration and so on. Atom is cross platform. It runs on Linux, Windows and macOS.


To Enable snaps on Debian and install Atom:

Snaps are applications packaged with all their dependencies to run on all popular Linux distributions from a single build. They update automatically and roll back gracefully. 

1. Enable snapd

$ sudo apt update
$ sudo apt install snapd
$ sudo snap install core

2. To install Atom, simply use the following command:

$ sudo snap install atom --classic


To Update Atom Text Editor on Debian:

You can update the Atom when a new version is available. You can update it through your desktop standard Software Update tool. 

Alternatively, you can update by running the following commands in your terminal:

$ sudo apt update
$ sudo apt upgrade

Install TeamViewer on Ubuntu 20.04 LTS - Step by Step Process ?

This article covers how to install TeamViewer on Ubuntu 20.04 via the command-line and GUI. You can also explore our related how-tos for Debian  and CentOS .

TeamViewer is a cross-platform solution that can be used for remote control, desktop sharing and file transfer between computers.


To Install TeamViewer on Ubuntu:

1. Open your terminal either by using the Ctrl+Alt+T keyboard shortcut or by clicking on the terminal icon.

Download the latest TeamViewer .deb package with the following wget command:

$ wget https://download.teamviewer.com/download/linux/teamviewer_amd64.deb

2. Install TeamViewer

Install the TeamViewer .deb package by issuing the following command as a user with sudo privileges:

$ sudo apt install ./teamviewer_amd64.deb

At the prompt Do you want to continue? [Y/n], type Y to continue the installation.


To Uninstall TeamViewer from Ubuntu System:

1. In order to uninstall TeamViewer from your system without removing any configurations you might have made, enter the following command as sudo:

$ sudo apt remove teamviewer

The system will prompt you with a Y/n option in order to begin the uninstall procedure. Please enter Y and hit Enter to begin. TeamViewer will then be removed from your system.

2. If you have made any configurations, you can remove TeamViewer and all those by using the following command:

$ sudo apt purge teamviewer

Set Up Postman on Ubuntu 20.04 - Step by Step Process ?

This article covers the method of installation of Postman on the Ubuntu 20.04 system. Also, we explored the method to set up Postman and how to send a request for the first time. 

Here, you will also learn the method of removing Postman application from system.


Postman is a complete API development platform that helps you manage your APIs in every stage of development, from designing and testing, to publishing API documentation and monitoring. 

Postman started as a Chrome browser extension and quickly became one of the most widely used API tools by developers all over the world.


Installing Postman on Ubuntu:

The easiest way is to install Postman on Ubuntu is by using the snappy packaging system. 

Snaps are self-contained software packages that include the binary all dependencies needed to run the application. Snap packages can be installed from either the command-line or via the Ubuntu Software application.

To install the Postman snap, open your terminal (Ctrl+Alt+T) and run the following command as a user with sudo privileges :

$ sudo snap install postman

Notch Up Producer-Consumer Paradigm with Python

This article covers how producer-Consumer pattern is a very useful design which can be leveraged to a varied extent in order to enable asynchronous processing of multiple time-consuming tasks. The concept has been widely incorporated in modern-day messaging queues viz. Kafka, RabbitMQ, Cloud MQs provided by AWS, GCP, and so on.

Python provide Queue class which implements queue data structure. We can put an item inside the queue and we can get an item from the queue. By default this works in FIFO (First In First Out) manner.


The function producer will put an item inside queue and function consumer will get an item from the queue. We will use following method of queue class by instantiating queue object q = Queue().


Queue Method Python:

q.put(): To put an item inside queue.

q.get(): To get an item which is present inside queue.

q.join(): This method stops python program from exiting till it gets signal from the below method task_done. Hence this method should always be used in conjunction with method task_done

q.task_done(): This method should be called when item got outside from the queue using q.get() has been completely processed by consumer. When all items make call to their respective task_done it sends signals to q.join() that all items have been processed and program can exit.


Threads class Python:

Python allows writing multi-threaded program using Thread class. We will instantiate object of thread class and make use of following methods to process (consume) multiple items concurrently:

t = Thread(target=consumer): Instantiate thread object which would make call to function consumer.

t.start(): Starts execution of thread by making call to function consumer.

Install VirtualBox on CentOS 8 - Step by Step Process ?

This article covers the complete installation guide of VirtualBox on the CentOS 8 system.

Oracle VirtualBox is a virtualization software solution that allows you to create and run virtual machines on a single hardware machine.

With VirtualBox, your existing operating system stays unaffected by the virtual environment.


To Start VirtualBox on Linux:

Use the command:

$ VirtualBox

The VirtualBox manager interface will prompt you.

Alternatively, you can use the graphical interface and access the application:

Application >> System Tools >> Oracle VM VirtualBox

Install IntelliJ IDEA on Ubuntu 20.04 LTS - Step by Step Process ?

This article covers the different methods to install IntelliJ IDEA on Ubuntu 20.04 Linux system. Basically, In developing Java applications, IntelliJ IDEA is arguably one of the most ergonomic and formidable IDEs there is. 

It ships with all the right tools and a set of plugins to make coding a seamless exercise.


To Install IntelliJ IDEA from command line on Ubuntu:

1. Start by opening a terminal window and execution of the bellow apt command. Select your preferred version to install:

$ sudo snap install intellij-idea-community --classic

OR

$ sudo snap install intellij-idea-ultimate --classic

OR

$ sudo snap install intellij-idea-educational --classic

2. You can start the IntelliJ IDEA using the below command:

$ intellij-idea-community

OR

$ intellij-idea-ultimate

OR

$ intellij-idea-educational

Install and Configure Redis in Ubuntu 20.04 - Step by step Process ?

This article covers the installing and configuring the Redis server on Ubuntu 20.04. #Redis is an in-memory key-value store known for its flexibility, performance, and wide language support. You can use it as a Memcached alternative to store simple key-value pairs. 


To Install and Configure Redis on Ubuntu:

In order to get the latest version of Redis, we will use apt to install it from the official Ubuntu repositories.

1. Update your local apt package cache and install Redis by typing:

$ sudo apt update
$ sudo apt install redis-server

This will download and install Redis and its dependencies. 

2. Following this, there is one important configuration change to make in the Redis configuration file, which was generated automatically during the installation.

Open this file with your preferred text editor:

$ sudo nano /etc/redis/redis.conf

Inside the file, find the supervised directive. This directive allows you to declare an init system to manage Redis as a service, providing you with more control over its operation. The supervised directive is set to no by default. Since you are running Ubuntu, which uses the systemd init system, change this to systemd.

3. Start by checking that the Redis service is running:

$ sudo systemctl status redis

4. If, however, you prefer to start up Redis manually every time your server boots, you can configure this with the following command:

$ sudo systemctl disable redis

5. To test that Redis is functioning correctly, connect to the server using the command-line client:

$ redis-cli

6. To restart Redis:

$ sudo systemctl restart redis.service

Install CouchDB on Ubuntu 20.04 - Step by Step Process ?

This article covers how to install CouchDB on Ubuntu Linux System. Apache offers us various options for working with data and information on the web and one of its many derivations is Apache CouchDB.

CouchDB is a popular NoSQL database developed and maintained by Apache Foundation since 2005. 

It is an open-source database written in Erlang language that provides a RESTful API that users can use to create and modify database objects. 


Main Features of CouchDB:

1. CouchDB has a clustered database, thus allowing you to run a logical database server regardless of the number of servers or virtual machines.

2. By using apache CouchDB we have a single node database which acts under an application server.

3. It makes use of the HTTP protocol and the JSON data format, being compatible with any software that supports them.

4. CouchDB's unique replication protocol generates "Offline First" applications for mobile applications and other environments that have infrastructure

high impact network.


To install Apache CouchDB on Ubuntu:

1. Enable the Apache CouchDB repository, for this we download and install the GPG key with the following command:

$ curl -L https://couchdb.apache.org/repo/bintray-pubkey.asc | sudo apt-key add - 

2. Now we add the repository, for this we execute:

$ sudo nano /etc/apt/sources.list 

3. At the bottom we add the line:

deb https://apache.bintray.com/couchdb-deb focal main 

4. We save the changes using the following key combination:

Ctrl + O

And exit the editor using:

Ctrl + X

5. We update the operating system with the following command.

$ sudo apt update

6. Next, we install Apache CouchDB:

$ sudo apt install apache2 couchdb 


To see the status of Apache CouchDB, run the command:

$ sudo systemctl status couchdb.service 

Check Open Ports on Ubuntu 20.04 Linux - How to do it ?

This article covers some common tools that can be used to check the open ports on a Linux system. It is important you verify which ports are listening on the server's network interfaces. You need to pay attention to open ports to detect an intrusion. 

Apart from an intrusion, for troubleshooting purposes, it may be necessary to check if a port is already in use by a different application on your servers. 

For example, you may install Apache and Nginx server on the same system. So it is necessary to know if Apache or Nginx is using TCP port # 80/443.


To check the listening ports and applications on Ubuntu Linux:

1. Open a terminal application i.e. shell prompt.

2. Run any one of the following command on Linux to see open ports:

$ sudo lsof -i -P -n | grep LISTEN
$ sudo netstat -tulpn | grep LISTEN
$ sudo ss -tulpn | grep LISTEN
$ sudo lsof -i:22 ## see a specific port such as 22 ##
$ sudo nmap -sTU -O IP-address-Here

For the latest version of Linux use the ss command. For example, ss -tulw


What is the netstat command ?

You can check the listening ports and applications with netstat as follows.

Run netstat command along with grep command to filter out port in LISTEN state:

$ netstat -tulpn | grep LISTEN

The netstat command deprecated for some time on Linux. Therefore, you need to use the ss command as follows:

$ sudo ss -tulw
$ sudo ss -tulwn
$ sudo ss -tulwn | grep LISTEN

Install Terraform on Ubuntu 18.04 / 20.04 LTS - Step by step process ?

This article covers how to install Terraform on Ubuntu. Terraform is an infrastructure automation tool which allows you to define and describe your infrastructure as code inside configuration files using a declarative language and to deploy and manage that infrastructure across a variety of public cloud providers like AWS, GCP, Azure, and so on.


To Install Terraform on Ubuntu:

1. First, create ~/bin directory:

$ mkdir ~/bin

2. Next, download the zip archive. Visit the Terraform download page for the latest version to download:

$ wget https://releases.hashicorp.com/terraform/0.12.24/terraform_0.12.24_linux_amd64.zip

3. Unzip the archive. 

The archive will extract a single binary called terraform.

$ unzip terraform_0.12.24_linux_amd64.zip

4. Move the terraform binary to a directory included in your system's PATH in our case that's ~/bin directory.

$ mv terraform ~/bin

5. To check whether Terraform is installed, run:

$ terraform version

Monitor Network Traffic with vnStat on Ubuntu 20.04 - How to do it ?

This article covers how to install and use this tool on Ubuntu 20.04 LTS for monitoring the traffic on network interfaces.

vnStat is a handy tool to keep an eye on the bandwidth usage on your Linux OS.


To Install vnstat using the apt/apt-get on Ubuntu:

1. Type the following apt command/apt-get command to update the system:

$ sudo apt update
$ sudo apt upgrade

2. Search for vnstat package, enter:

$ apt show vnstat

3. Execute the following command to set up and install vnstat on Ubuntu server:

$ sudo apt-get install vnstat

OR

$ sudo apt install vnstat


To Enable and start the vnstat service on Ubuntu:

Run the command below:

$ sudo systemctl enable vnstat.service

To Start the vnstat service

$ sudo systemctl start vnstat.service

To Stop the vnstat service

$ sudo systemctl stop vnstat.service

To Restart/reload the vnstat service

After editing the /etc/vnstat.conf, we must restart or reload the service:

$ sudo systemctl restart vnstat.service

OR

$ sudo systemctl reload vnstat.service

To Find the status of vnstat service

$ sudo systemctl status vnstat.service

Flush DNS Cache on Ubuntu 20.04 - Step by Step process ?

This article covers how to flush the DNS cache on Ubuntu. If the sites are not loading properly or you are receiving outdated sites, try to flush the DNS cache to see if the issue resolves. 

Remember, after the DNS cache is flushed, sites will first load slightly slower. 

But once the DNS cache is re-populated, sites will be loaded faster.


Facts about flushing DNS cache on Ubuntu:

1. DNS cache is a temporary database that stores information about previous DNS lookups. 

2. Whenever you visit a website, your OS and web browser will keep a record for the domain and the corresponding IP address. 

3. Flushing DNS cache eliminates the need for repetitive queries to the remote DNS servers and allows your OS or browser to resolve the website's URL quickly.


How to use dns-clean to flush DNS-Cache ?

You can clear the DNS cache is by starting the dns-clean utility. Run the following command in your Terminal to do so:

$ sudo /etc/init.d/dns-clean start

Install Atom Editor on Ubuntu 20.04 - Step by step process ?

This article covers the different methods to install Atom editor on Ubuntu 20.04 system. Atom is an open-source text and source code editor for Windows, Linux, and macOS, developed by GitHub. 

It is called "A hackable text editor for the 21st century" due to being a highly customizable text editor.


To Install Atom Editor using Snap:

1. First, install the Snap package manager on your system if it is not already installed.

$ sudo apt update && sudo apt install -y snapd

2. Then, install Atom editor with the snap command.

$ sudo snap install atom --classic

Install Dropbox on Ubuntu 20.04 - Step by step process ?

This article covers how to install Dropbox on your Ubuntu 20.04 system. Dropbox online storage provides us support for Ubuntu Linux. 

Dropbox provides us online storage to store or backup our data automatically. We use Dropbox to backup our contents with some security and peace of mind. 

In the event of our PCs crash, Our data will be saved and ready to be restored onto server.


To install Dropbox from Command Line on Ubuntu:

1. Install the wget package using the apt command,

$ sudo apt-get update
$ sudo apt-get install wget

2. Dropbox cli version is available for both 32 and 64 bit editions, we will download Dropbox upon out version.

For 32-bit,

$ cd ~ && wget -O - "https://www.dropbox.com/download?plat=lnx.x86" | tar xzf -

For 64-bit, 

$ cd ~ && wget -O - "https://www.dropbox.com/download?plat=lnx.x86_64" | tar xzf -

3. Run the following command to start the Dropbox from .dropbox-dist folder.

$ ~/.dropbox-dist/dropboxd


To manage Dropbox service:

1. Enable dropbox service using command below.

$ sudo systemctl enable dropbox

2. Start dropbox service using command below.

$ sudo systemctl start dropbox

3. Check running of the service using command below.

$ sudo systemctl status dropbox

Password Protect a File Using Vim on Ubuntu - Step by Step process ?

This article covers how to password protect a file using Vim on Linux.  When password protecting a file, make sure you remember it, or else you will not be able to access your file.

You can also use a password management software if you find it difficult to remember passwords. Or visit our guide on how to install Teampass password manager on Ubuntu .

Always remember to appropriately secure text files that could contain secret info such as usernames and passwords, financial account info and so on, using strong encryption and a password.


To install VIM in Linux:

Vim is available in the repositories of most major distributions. 

So, use your distribution package manager to get installed.

For Debian based systems, use apt-get or apt package manager to install vim.

$ sudo apt-get install vim

For RHEL/CentOS based systems, use yum package manager to install vim.

$ sudo yum install vim-enhanced

For Fedora system, use dnf package manager to install vim.

$ sudo dnf install vim-enhanced

For openSUSE system, use zypper package manager to install pass.

$ sudo zypper in vim

For Arch Linux based systems, use pacman package manager to install vim.

$ sudo pacman -S vim

Install R on Ubuntu 20.04 - Step by Step process ?

This article covers R installation on Ubuntu 20.04 system. R is an open-source programming language, R is widely used for performing data analysis and statistical computing. Supported by the R Foundation for Statistical Computing, it is an increasingly popular and extensible language with an active community. R offers many user-generated packages for specific areas of study, which makes it applicable to many fields.


To Install R on Ubuntu:

1. Add the relevant GPG key,

$ sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys E298A3A825C0D65DFD57CBB651716619E084DAB9

2. Add the repository,

$ sudo add-apt-repository 'deb https://cloud.r-project.org/bin/linux/ubuntu focal-cran40/'

3. Run update after this in order to include package manifests from the new repository.

$ sudo apt update

4. Install R with the following command:

$ sudo apt install r-base

If prompted to confirm installation, press y to continue.

Asynchronous Programming in Python - More about this ?

This article covers how to make applications performant and efficiently use CPU cycles and threads. However, it is not all rainbows and unicorns when talking about asynchronous code.

Asynchronous programming is a type of parallel programming in which a unit of work is allowed to run separately from the primary application thread. When the work is complete, it notifies the main thread about completion or failure of the worker thread. 

There are numerous benefits to using it, such as improved application performance and enhanced responsiveness.

On the other hand, A synchronous program is executed one step at a time. Even with conditional branching, loops and function calls, you can still think about the code in terms of taking one execution step at a time. When each step is complete, the program moves on to the next one.


Examples of synchronous program:

1. Batch processing programs are often created as synchronous programs. You get some input, process it, and create some output. Steps follow one after the other until the program reaches the desired output. The program only needs to pay attention to the steps and their order.

2. Command-line programs are small, quick processes that run in a terminal. These scripts are used to create something, transform one thing into something else, generate a report, or perhaps list out some data. This can be expressed as a series of program steps that are executed sequentially until the program is done.

Configure WordPress on Ubuntu Server with Apache - Step by step process to do it ?

This article covers setup WordPress — including Apache, MySQL, and PHP, on the Ubuntu Linux server. WordPress is the most popular CMS (content management system) on the internet. It allows you to easily set up flexible blogs and websites on top of a MySQL backend with PHP processing. WordPress has seen incredible adoption and is a great choice for getting a website up and running quickly. After setup, almost all administration can be done through the web frontend.


How to install PHP Extensions on Ubuntu?

1. You can download and install some of the most popular PHP extensions for use with WordPress by executing the commands:

$ sudo apt update
$ sudo apt install php-curl php-gd php-mbstring php-xml php-xmlrpc php-soap php-intl php-zip

2. Then restart Apache to load these new extensions in the next section. 

If you are returning here to install additional plugins, you can restart Apache now by running:

$ sudo systemctl restart apache2


To install WordPress on Ubuntu:

1. Change into a writable directory and then download the compressed release by typing:

$ cd /tmp
$ curl -O https://wordpress.org/latest.tar.gz

2. Extract the compressed file to create the WordPress directory structure:

$ tar xzvf latest.tar.gz

3. Add a dummy .htaccess file so that this will be available for WordPress to use later.

Create the file by typing:

$ touch /tmp/wordpress/.htaccess

4. Copy over the sample configuration file to the filename that WordPress actually reads:

$ cp /tmp/wordpress/wp-config-sample.php /tmp/wordpress/wp-config.php

5. Create the upgrade directory, so that WordPress won't run into permissions issues when trying to do this on its own following an update to its software:

$ mkdir /tmp/wordpress/wp-content/upgrade

6. Copy the entire contents of the directory into our document root:

$ sudo cp -a /tmp/wordpress/. /var/www/wordpress

Install Yarn on Ubuntu 20.04 - Step by step process to implement it ?

This article covers how to install Yarn on Ubuntu 20.04 LTS system. Yarn is a JavaScript package manager compatible with npm that helps you automate the process of installing, updating, configuring, and removing npm packages. 

It caches every download package and speeds up the installation process by parallelizing operations.


To Yarn on Ubuntu Linux:

1. Import the repository’s GPG key and add the Yarn APT repository to your system by running the following commands:

$ curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -
$ echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list

2. Once the repository is enabled, update the package list, and install Yarn:

$ sudo apt update
$ sudo apt install yarn

3. If you installed Node trough nvm, skip the Node.js installation with:

$ sudo apt install --no-install-recommends yarn

4. Once completed, verify the installation by printing the Yarn version:

$ yarn --version

Download YouTube Videos on Ubuntu Linux - How to do it ?

This article covers how you can download YouTube videos on Linux using the youtube-dl utility. The youtube-dl is a handy utility with a large feature set. However, there is a lot more you can do with this utility. To explore more features, visit its official documentation . To play the downloaded videos, you can use any media players like VLC , FFmpeg , and so on.

youtube-dl is a command-line program that lets you easily download videos and audio from more than a thousand websites. 


youtube-dl is a Python based small command-line tool that allows to download videos from YouTube.com, Dailymotion, Google Video, Photobucket, Facebook, Yahoo, Metacafe, Depositfiles and few more similar sites. 

It written in pygtk and requires Python interpreter to run this program, it's not platform restricted. It should run on any Unix, Windows or in Mac OS X based systems.


To Install YouTube-DL in RHEL/CentOS and Fedora:

The youtube-dl program can be installed by enabling epel repository under your systems. Once enabled, you can install using 'yum' package manager tool:

$ yum install youtube-dl

Also, if you wish to add any third party repository, you can still install it right away using curl or wget command:

$ curl https://yt-dl.org/latest/youtube-dl -o /usr/local/bin/youtube-dl

OR

$ wget https://yt-dl.org/downloads/latest/youtube-dl -O /usr/local/bin/youtube-dl

Your system must have curl or wget packages installed to fetch the recent version youtube-dl file. If you don't have them, you may yum to get it.

After fetching the file, you need to set a executable permission on the script to execute properly:

$ chmod a+rx /usr/local/bin/youtube-dl


To Install YouTube-DL in Ubuntu/Linux Mint and Debian:

$ sudo add-apt-repository ppa:nilarimogard/webupd8
$ sudo apt-get update
$ sudo apt-get install youtube-dl

Also, instead using any third party PPA, you can use curl or wget command to install latest version of youtube-dl script:

$ sudo curl https://yt-dl.org/latest/youtube-dl -o /usr/local/bin/youtube-dl

OR

$ sudo wget https://yt-dl.org/downloads/latest/youtube-dl -O /usr/local/bin/youtube-dl

After downloading the script, set the executable permission:

$ sudo chmod a+rx /usr/local/bin/youtube-dl


To Update YouTube-DL,

Youtube-dl itself can be updated to the latest version using the following command:

$ youtube-dl -U

Configure XRDP to Securely Connect Remote Linux Servers - Step by step process ?

This article covers how to install and use XRDP to securely connect to remote servers. Xrdp is an open-source implementation of the Microsoft Remote Desktop Protocol (RDP) that allows you to control a remote system graphically. 

With RDP, you can log in to the remote machine and create a real desktop session the same as if you had logged in to a local machine.


Installing Xrdp on Debian:

Xrdp package is available in the standard Debian repositories. To install it, run:

$ sudo apt install xrdp 

The service will automatically start once the installation process is complete. You can verify that the Xrdp service is running by typing:

$ sudo systemctl status xrdp


How to Configure Xrdp on Linux?

The Xrdp configuration files are stored in the /etc/xrdp directory.

Whenever you make any changes to the configuration file you need to restart the Xrdp service:

$ sudo systemctl restart xrdp

View Standard Log Files on Ubuntu Linux Servers - How to do it ?

This article covers how to view standard log files for troubleshooting any Linux system. Linux system administrators often need to look at log files for troubleshooting purposes.

Linux and the applications that run on it can generate all different types of messages, which are recorded in various log files. Linux uses a set of configuration files, directories, programs, commands and daemons to create, store and recycle these log messages. 

Knowing where the system keeps its log files and how to make use of related commands can therefore help save valuable time during troubleshooting.


To view log files on Linux:

Open the Terminal or login as root user using ssh command. 

Go to /var/log directory using the following cd command:

# cd /var/log

To list files use the following ls command:

# ls


To Configure Log Files on Ubuntu and CentOS:

This section explains different mechanisms for configuring log files. Let's start with a CentOS example.

To view users currently logged onto a Linux server, enter the who command as a root user:

$ who

This also lists the login history of users. 

To view the login history of the system administrator, enter the following command:

$ last reboot

To view information of the last login, enter:

$ lastlog


To Execute Log Rotation on Linux:

Log files that have zeroes appended at the end are rotated files. That means log file names have automatically been changed within the system.

The purpose of log rotation is to compress outdated logs that are taking up space. Log rotation can be done using the logrotate command. This command rotates, compresses, and mails system logs.

logrotate handles systems that create significant amounts of log files. The command is used by the cron scheduler and reads the logrotate configuration file /etc/logrotate.conf. It's also used to read files in the logrotate configuration directory.

Install and Use Curl Command on Ubuntu 20.04 - Step by step process to implement it ?

This article covers how to set up curl command on your Ubuntu 20.04 LTS machine. curl command is a tool to download or transfer files/data from or to a server using FTP, HTTP, HTTPS, SCP, SFTP, SMB and other supported protocols on Linux or Unix-like system.


To Install cURL for Ubuntu Linux:

1. Update your Ubuntu box, run: 

$ sudo apt update && sudo apt upgrade

2. Next, install cURL, execute: 

$ sudo apt install curl

3. Verify install of curl on Ubuntu by running: 

$ curl --version

Use SED Command to Find and Replace String in Files - How to perform this task on Ubuntu?

This article covers how to use the Sed command on Ubuntu 20.04. Searching and replacing a string of text in a file with the Sed command isn't complicated as you imagine.

sed is a stream editor. It can perform basic text manipulation on files and input streams such as pipelines. 

With sed, you can search, find and replace, insert, and delete words and lines. 

It supports basic and extended regular expressions that allow you to match complex patterns.


To Find and replace text within a file using sed command:

The procedure to change the text in files under Linux/Unix using sed:

1. Use Stream EDitor (sed) as follows:

$ sed -i 's/old-text/new-text/g' input.txt

2. The s is the substitute command of sed for find and replace

3. It tells sed to find all occurrences of 'old-text' and replace with 'new-text' in a file named input.txt

4. Verify that file has been updated:

more input.txt

Install Cockpit on Ubuntu 20.04 - Step by step process to do this ?

This article covers how to install Cockpit on Ubuntu 20.04 system. Cockpit is a free and open source web console tool for Linux administrators and used for day to day administrative and operations tasks. 


To Install the Cockpit package on Ubuntu 20.04 LTS Server, run the command:

$ sudo apt update
$ sudo apt install cockpit -y

Once cockpit package is installed successfully then start its service using the following systemctl command,

$ sudo systemctl start cockpit

Run the following to verify the status of cockpit service,

$ sudo systemctl status cockpit


Features of Cockpit:

Cockpit allows you to perform:

1. Service Management – Start, stop, restart, reload, disable, enable, mask e.t.c

2. User Account Management – Add users, delete, Lock, assign Administrator role, set password, force password change, Add Public SSH keys e.t.c.

3. Firewall Management

4. Cockpit Container management

5. SELinux Policy management

6. Journal v2

7. iSCSI Initiator configurations

8. SOS-reporting

9. NFS Client setup

10. Configure OpenConnect VPN Server

11. Privileged Actions – Shutdown, Restart system

12. Join Machine to Domain

13. Hardware Device Management

14. System Updates for dnf, yum, apt hosts

15. Manage the Kubernetes Node

Install XAMPP on CentOS 8 - Step by Step process to do this ?

This article covers how to install XAMPP on your CentOS system. XAMPP is an easy to install and use Apache distribution packaged with MariaDB, PHP, and Perl.

XAMPP was first developed by a project team called Apache Friends. As an open-source Apache distribution of a PHP development environment, it consists of cross-platform software (X): Apache (A), MariaDB (M), PHP (P) and Perl (P). 


To install XAMPP on CentOS 8 Linux system:

1. Update system

Ensure your CentOS system is updated.

$ sudo dnf -y update
$ sudo dnf -y install libnsl

2. Download XAMPP on CentOS 8

Install wget on CentOS 8:

$ sudo dnf -y install wget

Download XAMPP installer. Choose the installer matching the PHP version you want to have.

### PHP 8.0 ###

$ wget https://www.apachefriends.org/xampp-files/8.0.1/xampp-linux-x64-8.0.1-0-installer.run

### PHP 7.4 ###

$ wget https://www.apachefriends.org/xampp-files/7.4.14/xampp-linux-x64-7.4.14-0-installer.run

### PHP 7.3 ###

$ wget https://www.apachefriends.org/xampp-files/7.3.26/xampp-linux-x64-7.3.26-0-installer.run

3. The binary installer should be executable.

### PHP 8.0 ###

$ chmod a+x xampp-linux-x64-8.0.1-0-installer.run

### PHP 7.4 ###

$ chmod a+x xampp-linux-x64-7.4.14-0-installer.run

### PHP 7.3 ###

$ chmod a+x xampp-linux-x64-7.3.26-0-installer.run

4. Then run the XAMP installer:

### PHP 8.0 ###

$ sudo ./xampp-linux-x64-8.0.1-0-installer.run

### PHP 7.4 ###

$ sudo ./xampp-linux-x64-7.4.14-0-installer.run

### PHP 7.3 ###

$ sudo ./xampp-linux-x64-7.3.26-0-installer.run


How to Start and use XAMPP on CentOS 8:

XAMPP is installed to /opt/lampp/. To start XAMPP services, run:

$ sudo /opt/lampp/lampp start

To verify installation of XAMPP on CentOS 8 visit the Apache web page:

http://localhost


Stopping and Uninstalling XAMPP on CentOS 8:

To stop XAMPP services run:

$ sudo /opt/lampp/lampp stop

To uninstall XAMPP on CentOS 8, run:

$ cd /opt/lampp
$ sudo ./uninstall
$ sudo rm-rf /opt/lampp

Install TeamViewer on Debian 10 - Step by Step process ?

This article covers how to install TeamViewer on Debian 10. TeamViewer is a cross-platform application that can be used for remote control, desktop sharing, online meetings, and file transfer between computers.


To install TeamViewer on Debian:

TeamViewer is proprietary computer software, and it is not included in the default Debian repositories.

TeamViewer maintains its own APT repository from which we’ll install the package, and update it when a new version is available.

1. Download TeamViewer

Open your terminal either by using the Ctrl+Alt+T keyboard shortcut or by clicking on the terminal icon.

Use wget to download the latest TeamViewer .deb package:

$ wget https://download.teamviewer.com/download/linux/teamviewer_amd64.deb

2. Install TeamViewer

Install the downloaded .deb package by typing the following command:

$ sudo apt install ./teamviewer_amd64.deb

When prompted Do you want to continue? [Y/n], type Y to continue the installation.

Setup Git Server on Ubuntu 20.04 - Step by Step process ?

This article covers how to install and configure a Git server on Ubuntu. Git is basically a Version control system which allows you to keep track of your software at the source level. With Git, You can easily track changes, revert to previous stages, and branch to create alternate versions of files and directories.


To install Git on Ubuntu Server:

1. Run the following commands as sudo user:

$ sudo apt update && sudo apt install git

2. To install the git package on CentOS servers type:

$ sudo yum install git

3. Next, create a new user that will manage the Git repositories:

$ sudo useradd -r -m -U -d /home/git -s /bin/bash git

The user home directory is set to /home/git

All the repositories will be stored under this directory.

Install Go on Ubuntu 20.04 - Step by step process to do it ?

This article covers how to install Go on your Ubuntu 20.04 machine. Now you can start programming Go language. Go is a popular programming language created by Google. 

Many modern applications such as Docker, Kubernetes, and Caddy are written in Go.


To install Go on Ubuntu:

1. Use curl or wget to download the current binary for Go from the official download page. As of this writing, the current version is 1.12.9. 

Check the download page for updates, and replace 1.12.9 with the most recent stable version if necessary:

$ curl -O https://storage.googleapis.com/golang/go1.12.9.linux-amd64.tar.gz

Verify the .tar file using sha256sum:

$ sha256sum go1.12.9.linux-amd64.tar.gz

3. Extract the tarball:

$ tar -xvf go1.12.9.linux-amd64.tar.gz

4. Adjust the permissions and move the go directory to /usr/local:

$ sudo chown -R root:root ./go
$ sudo mv go /usr/local

Install Memcached on Ubuntu 20.04 - Step by step process ?

This article covers how you can install Memcached on Ubuntu 20.04. Memcached has proved to be a very reliable caching system since its inception in 2003 and continues to be a favorite among developers in speeding up web applications. 

Memcached is a high-performance, distributed memory object caching server. It is free and open source software intended for use in speeding up dynamic web applications by mitigating database load.


To install and configure memcached on Ubuntu:

1. Update your Ubuntu server:

$ sudo apt update
$ sudo apt upgrade

2. Install memcached server on Ubuntu:

Run apt command as follows:

$ sudo apt install memcached

3. Configure memcached server:

Edit config file named /etc/memcached.conf using a text editor such as nano command or vim command:

$ sudo nano /etc/memcached.conf

OR

$ sudo vi /etc/memcached.conf


How to restart, stop, reload memcached server on Ubuntu:

To Stop service - $ sudo systemctl stop memcached

To start Service - $ sudo systemctl start memcached

To restart Service - $ sudo systemctl restart memcached

To check the status - $ sudo systemctl status memcached

Install and Use Firewalld in CentOS / RHEL - Step by step process to implement it ?

This article covers method to Install and Use Firewalld in CentOS in order to increase the security of your Linux system. Note that the host-based firewall like firewalld is recommended by compliances like PCI DSS. 

FirewallD is a complete firewall solution that manages the system's iptables rules and provides a D-Bus interface for operating on them. Starting with CentOS 7, FirewallD replaces iptables as the default firewall management tool.

Firewalld services are predefined rules that apply within a zone and define the necessary settings to allow incoming traffic for a specific service.


How to install Firewalld on CentOS?

Firewalld is installed by default on CentOS 7, but if it is not installed on your system, you can install the package by running the command:

$ sudo yum install firewalld

Firewalld service is disabled by default. You can check the firewall status with:

$ sudo firewall-cmd --state

If you just installed or never activated before, the command will print not running. Otherwise, you will see running.

To start the FirewallD service and enable it on boot type:

$ sudo systemctl start firewalld
$ sudo systemctl enable firewalld


To open HTTP and HTTPS ports add permanent service rules to the dmz zone:

$ sudo firewall-cmd --permanent --zone=dmz --add-service=http
$ sudo firewall-cmd --permanent --zone=dmz --add-service=https

Make the changes effective immediately by reloading the firewall:

$ sudo firewall-cmd --reload

Zones provided by FirewallD:

1. drop: All incoming connections are dropped without any notification. Only outgoing connections are allowed.

2. block: All incoming connections are rejected with an icmp-host-prohibited message for IPv4 and icmp6-adm-prohibited for IPv6n. Only outgoing connections are allowed.

3. public: For use in untrusted public areas. You do not trust other computers on the network, but you can allow selected incoming connections.

4. external: For use on external networks with NAT masquerading enabled when your system acts as a gateway or router. Only selected incoming connections are allowed.

5. internal: For use on internal networks when your system acts as a gateway or router. Other systems on the network are generally trusted. Only selected incoming connections are allowed.

6. dmz: Used for computers located in your demilitarized zone that have limited access to the rest of your network. Only selected incoming connections are allowed.

7. work: Used for work machines. Other computers on the network are generally trusted. Only selected incoming connections are allowed.

8. home: Used for home machines. Other computers on the network are generally trusted. Only selected incoming connections are allowed.

9. trusted: All network connections are accepted. Trust all of the computers in the network.

Install and Use Veracrypt on Ubuntu 20.04 - Step by Step process to do it ?

This article covers how to Install and Setup VeraCrypt on Ubuntu 20.04. VeraCrypt, a fork of TrueCrypt, is a free and open source on-the-fly disk encryption (OTFE) tool.


Main features offered by VeraCrypt include:

1. Creates a virtual encrypted disk within a file and mounts it as a real disk.

2. Encrypts an entire partition or storage device such as USB flash drive or hard drive.

3. Encrypts a partition or drive where Windows is installed (pre-boot authentication).

4. Encryption is automatic, real-time(on-the-fly) and transparent.

5. Parallelization and pipelining allow data to be read and written as fast as if the drive was not encrypted.

6. Encryption can be hardware-accelerated on modern processors.

7. Provides plausible deniability, in case an adversary forces you to reveal the password: Hidden volume (steganography) and hidden operating system.


To Install VeraCrypt Using DEB binary Package on Ubuntu:

Debian/Ubuntu packages for VeraCrypt are also available for download on download’s page. However, as of this writing, there is not available a binary package for Ubuntu 20.04 yet. As such, we using binary package for Ubuntu 19.04.

Note that the installers are also available, both for GUI and console based installations.

To install console-based VeraCrypt;

wget https://launchpad.net/veracrypt/trunk/1.24-update4/+download/veracrypt-console-1.24-Update4-Ubuntu-19.10-amd64.deb

Then install it;

$ dpkg -i veracrypt-console-1.24-Update4-Ubuntu-19.10-amd64.deb

To install GUI based;

$ wget https://launchpad.net/veracrypt/trunk/1.24-update4/+download/veracrypt-1.24-Update4-Ubuntu-19.04-amd64.deb

Next, use APT package manager to ensure that any would-be dependency is dealt with automatically:

$ apt install ./veracrypt-1.24-Update4-Ubuntu-19.04-amd64.deb

You can uninstall GUI based VeraCrypt by executing;

$ apt remove --purge veracrypt
$ apt autoremove

Use Speedtest CLI to Test Internet Speed on Ubuntu 20.04 - How to perform this task ?

This article covers how to install and use the Speedtest CLI utility to test your Internet speed while using Ubuntu 20.04.


To check my Internet speed in Ubuntu:

1. Open the Ubuntu Terminal by pressing Ctrl+alt+T or through the Dash. 

2. Then enter the command to install python:

$ sudo apt-get install python-pip

Once python is successfully installed, use the command to install the speedtest-cli tool:

$ sudo pip install speedtest-cli

The tool will be installed in your system.


To check Your Internet Speed:

Run the following command to test your internet speed:

$ speedtest-cli


To share Internet Speed Test Results:

The speedtest-cli also lets you share your internet speed by providing a link on the speedtest.net website through the following command:

$ speedtest-cli --share

Install Docker Compose on Ubuntu 20.04 - Step by step process to perform it ?

This article covers how to install and run Docker Compose on your Ubuntu 20.04 LTS machine. Docker Compose is yet another useful Docker tool. It allows users to launch, execute, communicate, and close containers with a single coordinated command. Essentially, Docker Compose is used for defining and running multi-container Docker applications.


To Install Docker Compose on Ubuntu:

1. Start by updating the default repository to ensure you download the latest Docker Compose:

$ sudo apt update

2. Then, upgrade the system to ensure all local packages and programs are up to date:

$ sudo apt upgrade

3. Then install Docker Compose from the Ubuntu repository by running:

$ sudo apt install docker-compose


To install Install curl on Ubuntu:

To download the binary package using an URL, you need curl. You can check whether you have this command-line utility by typing in the terminal window:

$curl

If the output displays "try 'curl --help' or 'curl --manual' for more information", move on to the next step. 

This message means curl is installed.

However, if the terminal says "command not found", you need to install curl with:

$ sudo apt install curl


To Check Docker Compose Version on Ubuntu:

To verify the installation, check the Docker Compose version by running:

$ docker–compose –version


To uninstall Docker Compose on Ubuntu:

Uninstalling Docker Compose from your Ubuntu system is a simple 3-step process.

1. Delete the Binary

First, delete the binary with the command:

$ sudo rm /usr/local/bin/docker-compose

2. Uninstall the Package

Then, use the apt remove command to uninstall the software:

$ sudo apt remove docker-compose

3. Remove Software Dependencies

Finally, remove the unwanted software dependencies by running:

$ sudo apt autoremove

Install Sublime Text Editor on CentOS 8 - Step by Step process to do it ?

This article covers how to install sublime text editor on the CentOS 8 system through the terminal. Sublime text editor is quite similar to vim editor. Sublime text has a built-in Python API available in Windows, Linux, and Mac OS.


To install Sublime Text on Ubuntu:

1. Install the GPG key:

$ wget -qO - https://download.sublimetext.com/sublimehq-pub.gpg | sudo apt-key add -

2. Ensure apt is set up to work with https sources:

$ sudo apt-get install apt-transport-https

3. Select the channel to use:

i. Stable

$ echo "deb https://download.sublimetext.com/ apt/stable/" | sudo tee /etc/apt/sources.list.d/sublime-text.list

ii. Dev

$ echo "deb https://download.sublimetext.com/ apt/dev/" | sudo tee /etc/apt/sources.list.d/sublime-text.list

4. Update apt sources and install Sublime Text:

$ sudo apt-get update
$ sudo apt-get install sublime-text


To fix yum-config-manager command not found:

You need to Install yum-utils by running the command below:

$ yum install yum-utils

Automatically Empty the Trash in Ubuntu 20.04 - How to do this ?

This article covers how to install Autotrash on Ubuntu system. With Autotrash, you can automatically delete the files residing in the Trash based on the conditions you specified.

trash-cli is a command-line interface to the trash-can used by Linux Systems. 

The trash-cli is present in repositories of most of the Linux Distributions.


To remove Autotrash from Ubuntu:

Run the command:

$ sudo snap remove autotrash-unofficial

Change Host Name on Ubuntu 20.04 - How to perform this task ?

This article covers both the CLI and GUI based methods of changing the hostname on Ubuntu 20.04. 

To change the hostname on Ubuntu Linux:

1. Type the following command to edit /etc/hostname using nano or vi text editor: $ sudo nano /etc/hostname. Delete the old name and setup new name.

2. Next Edit the /etc/hosts file: sudo nano /etc/hosts.

3. Reboot the system to changes take effect: sudo reboot.


To change the hostname on Ubuntu:

1. To change the hostname invoke the hostnamectl command with the set-hostname argument followed by the new hostname. 

2. Only the root or a user with sudo privileges can change the system hostname. 

3. The hostnamectl command does not produce output.


To change the localhost hostname (static name in the hostname file)?

1. You can also set the static hostname manually by editing /etc/hostname

2. This file contains exactly one line by default. 

3. If you have not changed the hostname yet, then that line probably reads localhost. localdomain .


To display the current Ubuntu hostname:

Simply type the following command:

$ hostnamectl


To change Ubuntu LTS hostname permanently:

1. Type the hostnamectl command :

$ sudo hostnamectl set-hostname newNameHere

2. Delete the old name and setup new name.

3. Next Edit the /etc/hosts file:

$ sudo nano /etc/hosts

Replace any occurrence of the existing computer name with your new one.

4. Reboot the system to changes take effect:

$ sudo reboot


To change hostname on Ubuntu without a system restart:

1. Let us see current setting just type the following command:

$ hostnamectl

2. Next change hostname from localhost to linuxapt, enter:

$ hostnamectl set-hostname linuxapt

3. Verify new changes:

$ hostnamectl

Install ClamAV Anti-Malware Protection on Ubuntu 20.04 - How to do this ?

This article covers how to install and configure ClamAV and ClamTK to scan for malware on Ubuntu 20.04. 

There aren't many viruses made for Linux distributions and as such, most people who use such systems don't even bother using antivirus software. 

Those however who do want to be able to scan their system or other Windows-based systems that are connected to a Linux PC through a network can use ClamAV. 

ClamAV is an open-source anti-virus engine that is built to detect viruses, trojans, malware, and other threats. 

It supports multiple file formats (documents, executables, or archives), utilizes multi-thread scanner features, and receives updates for its signature database at least 3-4 times a day.


To ClamAV Antivirus on Ubuntu:

The first step is to install and get the latest signature updates. To do this on Ubuntu, you can open a terminal and insert "sudo apt-get install clamav" and press enter.

$ sudo apt install clamav

You may also build ClamAV from sources to benefit from better scanning performance.

To update the signatures, you type "sudo freshclam" on a terminal session and press enter.

$ sudo freshclam

Now we are ready to scan our system. 

To do this, you can use the "clamscan" command. 

This is a rich command that can work with many different parameters so you'd better insert "clamscan –-help" on the terminal first and see the various things that what you can do with it:

$ clamscan –-help


To Update ClamAV Signature Database:

1. Stop the ClamAV process:

$ systemctl stop clamav-freshclam

2. Manually update the ClamAV signature database:

$ freshclam

3. Restart the service to update the database in the background:

$ systemctl start clamav-freshclam

Install Microsoft PowerShell in Ubuntu 20.04 - How to perform this task ?

This article covers the different methods for installing Microsoft PowerShell on Ubuntu which includes installation via package repository, via .deb package, and via snap. 

PowerShell for Linux is published to package repositories for easy installation and updates. 

As superuser, register the Microsoft repository once. 

After registration, you can update PowerShell with sudo apt-get install powershell.


To install PowerShell on Ubuntu 20.04:

PowerShell for Linux is published to package repositories for easy installation and updates.

So do the following;

1. # Update the list of packages.

$ sudo apt-get update

2. # Install pre-requisite packages.

$ sudo apt-get install -y wget apt-transport-https software-properties-common

3. # Download the Microsoft repository GPG keys.

$ wget -q https://packages.microsoft.com/config/ubuntu/20.04/packages-microsoft-prod.deb

4. # Register the Microsoft repository GPG keys.

$ sudo dpkg -i packages-microsoft-prod.deb

5. # Update the list of products.

$ sudo apt-get update

6. # Enable the "universe" repositories.

$ sudo add-apt-repository universe

7. # Install PowerShell.

$ sudo apt-get install -y powershell

8. # Start PowerShell.

$ pwsh

As superuser, register the Microsoft repository once.

After registration, you can update PowerShell with sudo apt-get install powershell.


To remove PowerShell from Ubuntu:

Run the command,

$ sudo apt-get remove powershell


How to Launch PowerShell on Linux or Mac?

1. Open a terminal and run the "powershell" command to access a PowerShell shell environment. 

2. This works on both Linux and Mac–whichever you're using. 

3. You'll see a PowerShell prompt beginning with "PS", and you can run PowerShell cmdlets just as you would on Windows.

Find out Which Groups a User Belongs to in Ubuntu 20.04 - How to do it ?

This article covers how you can easily find out which groups a user belongs to in Ubuntu. Also we shared how to list all groups in a system, list members of a group, add and remove a user from the group. For information about adding/removing users in a system, visit our guide on how to add and remove users on Ubuntu .

Adding a user to an existing group is one of the typical tasks of a Linux administrator.

A group is a collection of users. 

The main purpose of the group is to define a set of privileges to their members within the group.


To find out if a user has sudo access is by checking if the said user is member of the sudo group. 

If you see the group 'sudo' in the output, the user is a member of the sudo group and it should have sudo access.

In order to list groups on Linux, you have to execute the "cat" command on the "/etc/group" file. 

When executing this command, you will be presented with the list of groups available on your system.


To login as Sudo on Ubuntu:

1. Open a terminal Window. Press Ctrl + Alt + T to open the terminal on Ubuntu.

2. To become root user type: sudo -i. sudo -s.

3. When promoted provide your password.

4. After successful login, the $ prompt would change to # to indicate that you logged in as root user on Ubuntu.


What is /etc/passwd file?

"/etc/passwd" is a text file containing every user information that is required to login to the Linux system. It maintains useful information about users such as username, password, user ID, group ID, user information, home directory and shell.


To find out which groups a user belongs to in Linux:

1. groups: Show All Members of a Group.

2. id: Print user and group information for the specified username.

3. lid or libuser-lid: It display user's groups or group's users.

4. getent: Get entries from Name Service Switch libraries.

5. compgen: compgen is bash built-in command and it will show all available commands for the user.

6. members: List members of a group.

7. /etc/group file: Also, we can grep the corresponding user’s groups from the /etc/group file.


What is Wheel Group in Linux?

The wheel group is a special user group used on some Unix systems, mostly BSD systems, to control access to the su or sudo command, which allows a user to masquerade as another user (usually the super user). Debian-like operating systems create a group called sudo with purpose similar to that of a wheel group.


Types of groups in Linux:

1. Primary Group - The primary group is the main group associated with the user account. Each user must be a member of a single primary group.

2. Secondary Group - The secondary or supplementary group is used to grant additional rights to the user. Each user can become a member of multiple secondary groups.

Install Plex Media Server on Ubuntu 20.04 - Step by step process to get this done ?

This article covers the installation of the Plex media server on Ubuntu. Using the Plex, you can save all your favorite Tv shows, movies, videos, and photos in a single place. You can approach them from anywhere to any device. 


To install Plex Media Server on Ubuntu:

1. Download the .deb package

2. run sudo dpkg -i plexmediaserver_1.19.4.2935-79e214ead_amd64.deb (replacing the last filename with the name of the package you downloaded)

3. To setup Plex Media Server, on the same machine you installed the server on, open a browser window, and go to http://127.0.0.1:32400/web.


To Enable and start Plex media server on Ubuntu:

Execute the following command as sudo: $ sudo systemctl start plexmediaserver.service.

Setup Teampass Passwords Manager on Ubuntu 20.04 - Do it Now ?

This article covers perform the installation of TeamPass using the LAMP stack on Ubuntu. Now you can easily manage your credentials within your Organization to save credentials and manage access to every individual. 

TeamPass is a Collaborative Passwords Manager used for managing passwords and sharing them among team members.


To Download Teampass on Ubuntu:

1. Start by cloning the Teampass repository to your web server root directory as shown below;

$ git clone https://github.com/nilsteampassnet/TeamPass.git /var/www/html/teampass

2. Set the ownership of the teampass web directory to web server user (www-data)

$ chown -R www-data.www-data /var/www/html/teampass/

3. Next, edit the /etc/php/7.2/apache2/php.ini configuration file and increase the script execution time from 30 to 60 secs.

vim /etc/php/7.2/apache2/php.ini
...
;max_execution_time = 30
max_execution_time = 60
...

4. Restart Apache web server

$ systemctl restart apache2


To Finalize TeamPass installation on Ubuntu:

Final installation of Teampass can be done from the browser. 

Hence, navigate to the browser and enter the Teampass server URL, 

http://Server_IP/teampass

This will redirect you to Teampass welcome page

Install and Configure Apache Kafka on Ubuntu 20.04 - Step by Step process to implement this task ?

This article covers how to install and configure Apache Kafka on your Ubuntu 20.04 LTS machine. Apache Kafka is a distributed events streaming platform which has the ability to handle the high-performance data pipelines. It was originally developed by Linkedin then to be public as an open-source platform and used by many IT companies in the world.


Terms related to Apache Kafka Infrastructure:

1. Topic: A topic is a common name used to store and publish a particular stream of data. For example if you would wish to store all the data about a page being clicked, you can give the Topic a name such as "Added Customer".


2. Partition: Every topic is split up into partitions ("baskets"). When a topic is created, the number of partitions need to be specified but can be increased later as need arises. Each message gets stored into partitions with an incremental id known as its Offset value.


3. Kafka Broker: Every server with Kafka installed in it is known as a broker. It is a container holding several topics having their partitions.


4. Zookeeper: Zookeeper manages Kafka's cluster state and configurations.


Main advantages of using Apache Kafka:

1. Message Broking: In comparison to most messaging systems Kafka has better throughput, built-in partitioning, replication, and fault-tolerance which makes it a good solution for large scale message processing applications


2. Website Activity Tracking


3. Log Aggregation: Kafka abstracts away the details of files and gives a cleaner abstraction of log or event data as a stream of messages.


4. Stream Processing: capturing data in real-time from event sources; storing these event streams durably for later retrieval; and routing the event streams to different destination technologies as needed


5. Event Sourcing: This is a style of application design where state changes are logged as a time-ordered sequence of records.


6. Commit Log: Kafka can serve as a kind of external commit-log for a distributed system. The log helps replicate data between nodes and acts as a re-syncing mechanism for failed nodes to restore their data.


7. Metrics: This involves aggregating statistics from distributed applications to produce centralized feeds of operational data.


To install Apache Kafka on Ubuntu:

1. Update your fresh Ubuntu 20.04 server and get Java installed as illustrated below.

$ sudo apt update && sudo apt upgrade
$ sudo apt install default-jre wget git unzip -y
$ sudo apt install default-jdk -y

2. Fetch Kafka on Ubuntu 20.04.

$ cd ~
$ wget https://downloads.apache.org/kafka/2.6.0/kafka_2.13-2.6.0.tgz
$ sudo mkdir /usr/local/kafka-server && cd /usr/local/kafka-server
$ sudo tar -xvzf ~/kafka_2.13-2.6.0.tgz --strip 1

3. Create Kafka and Zookeeper Systemd Unit Files

i. Let us begin with Zookeeper service.

$ sudo vim /etc/systemd/system/zookeeper.service
[Unit]
Description=Apache Zookeeper Server
Requires=network.target remote-fs.target
After=network.target remote-fs.target
[Service]
Type=simple
ExecStart=/usr/local/kafka-server/bin/zookeeper-server-start.sh /usr/local/kafka-server/config/zookeeper.properties
ExecStop=/usr/local/kafka-server/bin/zookeeper-server-stop.sh
Restart=on-abnormal
[Install]
WantedBy=multi-user.target


ii. Then for Kafka service. Make sure your JAVA_HOME configs are well inputted or Kafka will not start.

$ sudo vim /etc/systemd/system/kafka.service
[Unit]
Description=Apache Kafka Server
Documentation=http://kafka.apache.org/documentation.html
Requires=zookeeper.service
After=zookeeper.service
[Service]
Type=simple
Environment="JAVA_HOME=/usr/lib/jvm/java-11-openjdk-amd64"
ExecStart=/usr/local/kafka-server/bin/kafka-server-start.sh /usr/local/kafka-server/config/server.properties
ExecStop=/usr/local/kafka-server/bin/kafka-server-stop.sh
Restart=on-abnormal
[Install]
WantedBy=multi-user.target


iii. Reload the systemd daemon to apply changes and then start the services. 

$ sudo systemctl daemon-reload
$ sudo systemctl enable --now zookeeper
$ sudo systemctl enable --now kafka
$ sudo systemctl status kafka zookeeper


4. Install Cluster Manager for Apache Kafka (CMAK) | Kafka Manager.

$ cd ~
$ git clone https://github.com/yahoo/CMAK.git


5. Configure CMAK on Ubuntu.

Add and Remove Users on Ubuntu 20.04 - How to perform this task ?

This article covers how you can add and remove users on Ubuntu and assign them administrator privileges. Based on your convenience, you can either choose to add and remove users either through the command line or GUI. 

Ubuntu, like any other Linux distribution, is a multi-user operating system. Each user can have different permission levels and specific settings for various command-line and GUI applications.

Knowing how to add and remove users is one of the basic skills a Linux user should know.


To add a user in Ubuntu via GUI:

1. Open the Activities overview and start typing Users.

2. Click on Users to open the panel.

3. Press Unlock in the top right corner and type in your password when prompted.

4. Press the + button, below the list of accounts on the left, to add a new user account.


To remove a user from Ubuntu:

1. Open the terminal app.

2. Login to server using the ssh user@server-ip-here command.

3. Run sudo deluser --remove-home userNameHere command to delete a user account on Ubuntu.

4. Verify it by running id command.


To Remove a Linux user:

1. Log in to your server via SSH.

2. Switch to the root user: sudo su -

3. Use the userdel command to remove the old user: userdel user's username.

Optional: You can also delete that user's home directory and mail spool by using the -r flag with the command: userdel -r user's username.


To Add a User to Linux:

1. Log in as root.

2. Use the command useradd "name of the user" (for example, useradd linuxapt)

3. Use su plus the name of the user you just added to log on.

4. "Exit" will log you out.


Linux operations commands:

1. adduser : add a user to the system.

2. userdel : delete a user account and related files.

3. addgroup : add a group to the system.

4. delgroup : remove a group from the system.

5. usermod : modify a user account.

6. chage : change user password expiry information.


How do I assign a user to a group in Linux?

1. To create a new group, enter the following: sudo groupadd new_group.

2. Use the adduser command to add a user to a group: sudo adduser user_name new_group.

3. To delete a group, use the command: sudo groupdel new_group.

4. Linux comes with several different groups by default.

Install TeamViewer on CentOS 8 - Step by Step process to get it done ?

This article covers how to install TeamViewer on the CentOS system. Additionally, you will learn how to install, launch, and update TeamViewer on CentOS.

We have also covered how to uninstall TeamViewer in case you no longer need it on your system. 

For some more help regarding TeamViewer, run teamviewer help in Terminal.

TeamViewer is a Robust cross-platform solution that provides secure remote access, remote control, and remote support solution across devices. 

The data traffic between devices are encrypted which makes the TeamViewer very secure. 

This software is available for “Linux, Windows, Mac, Chrome OS” and even for mobile devices like "iOS, Android, and so on".


To Install TeamViewer on CentOS 8:

1. Enable EPEL Repo on CentOS 8

You can install EPEL repo using the below command. This command will enable the repo if it is not already installed:

$ sudo yum install https://dl.fedoraproject.org/pub/epel/epel-release-latest-8.noarch.rpm -y

2. Now you can proceed further to install TeamViewer on CentOS 8:

$ sudo yum install teamviewer.x86_64.rpm -y

3. Once the package is installed you can start using team viewer:

$ teamviewer

Install Arduino IDE on Debian 10 - Step by Step Process to implement it ?

This article covers different methods to install the Arduino IDE on Debian system. To get the latest version of Arduino IDE, simply go for installation via tarball and snap. If you prefer an older release of Arduino, go for installation via apt.

Arduino boards are able to read inputs – light on a sensor, a finger on a button, or a Twitter message – and turn it into an output – activating a motor, turning on an LED, publishing something online. You can tell your board what to do by sending a set of instructions to the microcontroller on the board. 

To do so you use the Arduino programming language (based on Wiring), and the Arduino Software (IDE), based on Processing.”


To Install Arduino IDE on Ubuntu:

1. Execute the command:

$ sudo apt install Arduino

2. You will be provided with Y/N option, press y to continue.

3. Now wait for a while until the installation of Arduino IDE is completed.


To Launch Arduino IDE:

To launch Arduino IDE application on your system, hit the super key and in the search bar that appears, type Arduino. When the Arduino IDE icon appears, click on it to launch.

You will see the default view of Arduino IDE.

Install Skype on CentOS 8 - Step by Step process to implement it ?

This article covers how to install skype on the CentOS 8 system. One is using the RPM skype repository and another one is through the snap tool. 

Running Skype on CentOS/Fedora allows you to make Skype calls, group video calls, instant messaging, phone number calls, and screen sharing.


To Install Skype on CentOS:

1. Execute the command;

$ sudo yum localinstall skypeforlinux-64.rpm

2. Press y when prompted to confirm installation.


To Launch Skype on CentOS:

After successful installation, search Skype on your Desktop Environment search bar.

Install Nginx on Ubuntu 20.04 - Step by Step process to implement it ?

This article covers how to install Nginx on the Ubuntu system. Also, you will learn how to configure the firewall and manage Nginx services. 

Finally, you will see how to uninstall Nginx in case you no longer need it in your system.

Nginx is a free, open-source Linux application for web servers. It works as a reverse proxy server by directing web traffic to specific servers.

Also, Nginx is used for security and load-balancing, but can also function independently as a web server.


To Install Nginx From Ubuntu Repositories:

1. Update Software Repositories

It is important to refresh the repository lists before installing new software. This helps make sure that the latest updates and patches are installed.

Open a terminal window and enter the following:

$ sudo apt-get update

2. Nginx is included in the Ubuntu 20.04 default repositories. Install it by entering the following command:

$ sudo apt-get install nginx


How to manage Nginx on Ubuntu ?

The behavior of Nginx can be adjusted. Use this to start or stop Nginx, or to enable or disable Nginx at boot.

Start by checking the status of the Nginx service:

$ sudo systemctl status nginx

If the status displays active (running), Nginx has already been started. 

Press CTRL+z to exit the status display.

If Nginx is not running, use the following command to launch the Nginx service:

$ sudo systemctl start nginx

To set Nginx to load when the system starts, enter the following:

$ sudo systemctl enable nginx

To stop the Nginx service, enter the following:

$ sudo systemctl stop nginx

To prevent Nginx from loading when the system boots:

$ sudo systemctl disable nginx

To reload the Nginx service (used to apply configuration changes):

$ sudo systemctl reload nginx

For a hard restart of Nginx:

$ sudo systemctl restart nginx

To Test the Configuration

$ sudo nginx –t

The system should report that the configuration file syntax is OK, and that the configuration file test is successful.

Install KDE Plasma on Ubuntu 20.04 - Step by Step process to implement it ?

This article covers how to install KDE Plasma on Ubuntu 20.04 system. The Plasma desktop option will be available along with the standard Ubuntu system. Also, you will learn the steps to uninstall KDE Plasma from the Ubuntu system. 

KDE is the short form for K Desktop Environment.

Plasma is the desktop environment and KDE is the umbrella project responsible for the development of Plasma desktop and a bunch of other applications.


To Install KDE desktop environment on Ubuntu:

For KDE Full - This is the complete KDE pack. It comes with the complete package and core KDE plasma desktop. 

$ sudo apt install kde-full


For KDE Standard - It includes Plasma desktop with standard set of KDE apps such as Kate (default text editor), Konqueror (default web browser), Kget (Download Manager), KMail (email client), Dolphin (File Manager) and so on. 

$ sudo apt install kde-standard


To install KDE Plasma Desktop:

Run the command - $ sudo apt install kde-plasma-desktop

Install Flask on Ubuntu 20.04 - Step by Step process to implement it ?

This article covers how to install Flask on Ubuntu 20.04. Flask is a powerful web framework for any developer. Unlike Django , by default Flask doesn’t include ORM, form validation, or any other functionalities provided by third-party libraries. Flask is built with extensions in mind, which are Python packages that add functionality to a Flask application.

Flask packages are included in the official Ubuntu repositories and can be installed using the apt package manager. 

This is the simplest way to install Flask on Ubuntu 20.04, but not as flexible as installing in a virtual environment. 

Also, the version included in the repositories may lag behind the latest version of Flask.


To install Flask on Ubuntu 20.04:

1. Ubuntu 20.04 ships with Python 3.8. You can verify that Python is installed on your system by typing:

$ python3 -V

2. The recommended way to create a virtual environment is by using the venv module, which is provided by the python3-venv package. Run the following command to install the package:

$ sudo apt install python3-venv

3. Create a new directory for the Flask application and switch into it:

$ mkdir flask_app && cd flask_app

4. Run the following command inside the directory to create the virtual environment:

$ python3 -m venv venv

The command will create a directory called venv, which contains a copy of the Python binary, the Pip package manager , the standard Python library, and other supporting files. You can use any name you want for the virtual environment.

5. To start using the virtual environment, you need to activate it with the activate script:

source venv/bin/activate

6. Now that the virtual environment is activated, use the Python package manager pip to install Flask:

$ pip install Flask

7. To verify the installation, run the following command, which prints the Flask version:

$ python -m flask --version

List Installed Packages in Ubuntu 20.04 - How to perform this task ?

This article covers how you can list installed packages on Ubuntu 20.04 LTS system. Also, you can also filter a specific package from the list and count the number of installed packages on your system.


You can list all installed packages with apt command or apt-get command on Ubuntu Linux.

You need to use the apt or apt-get or dpkg command to list all installed packages on an Ubuntu Linux server from the bash shell prompt.


To see what packages are installed on Ubuntu Linux:

1. Open the terminal application or log in to the remote server using ssh (e.g. ssh user@sever-name).

2. Run command apt list --installed to list all installed packages on Ubuntu.

3. To display a list of packages satisfying certain criteria such as show matching apache2 packages, run apt list apache.


To List all installed packages only:

The apt command displays both installed and packages available to install:

$ apt list --installed


To list or find out if a specific package installed or not:

Run package policy as follows:

$ apt list -a pkgNameHere

Schedule a Job in Cron to Run Every Hour in Ubuntu 20.04 - How to implement it ?

This article covers how a cron job can be scheduled to run every hour on Ubuntu System. Most Linux users are familiar with the Crontab job scheduler, which acts as a silent daemon that performs all the tasks assigned to it automatically, without any human intervention. 

This job scheduler makes the life of a Linux user much easier, as the user can hand over all the frequently occurring tasks to the Crontab scheduler so that these tasks can be executed automatically according to a specified schedule.


To Start Crontab Service

Run the following command:

$ sudo systemctl start cron


To Check Status of Crontab Service

Execute the command:

$ sudo systemctl status cron


To Launch Crontab File:

Execute the command:

$ crontab –e


To Run a program or script every 5 or X minutes or hours on Linux:

1. Edit your cronjob file by running crontab -e command.

2. Add the following line for an every-5-minutes interval. */5 * * * * /path/to/script-or-program.

3. Save the file, and that is it.

Install Skype on Linux Mint 20 - How to perform this task ?

This article covers how to install Skype on Linux Mint 20 system. Skype is used to make free video and voice calls, send instant messages, and also to share files with other people on Skype.

However, if at any instance, you feel like you are getting more inclined towards some other application or Skype is not fulfilling your needs anymore, then you can easily remove it by following the removal method prescribed in this guide.


To Install Skype on Linux Mint using the Software Center:

1. Click ‘Menu’, type ‘Software Manager’ in the search box and launch it.

2. Search for ‘Skype’ in the Software Manager’s search box. You should see Skype and Skype (Flathub). These are just coming from two different sources. Click on only the “Skype” version. This is coming from the official Linux Mint’s Repository source.

3. Click “Install”, enter the Root password to complete the installation.

4. After the installation is complete, you can click on the “Launch” button or open the app from the “Applications” menu.

5. Start using Skype!

Install Skype on Ubuntu 20.04 - Step by Step process to perform it ?

This article covers the different methods to install Skype on Ubuntu 20.04 LTS including both the GUI and the command line. 


To install the Skype snap, open your terminal (Ctrl+Alt+T) and run the following command:

$ sudo snap install skype --classic

That's it. You have installed Skype on your Ubuntu machine, and you can start using it.


How to install Skype with apt on Ubuntu ?

Skype is available from the official Microsoft Apt repositories. To install it, follow the steps below:

1. Open your terminal and download the latest Skype .deb package using the following wget command:

$ wget https://go.skype.com/skypeforlinux-64.deb

2. Once the download is complete, install Skype by running the following command as a user with sudo privileges :

$ sudo apt install ./skypeforlinux-64.deb

You will be prompted to enter your password.

3. When a new version is released, you can update the Skype package through your desktop standard Software Update tool or by running the following commands in your terminal:

$ sudo apt update

$ sudo apt upgrade

Install Apache Web Server on CentOS 8 - Step by Step process to do it ?

This article covers how to install Apache web server on CentOS 8 distribution. With Apache we server, you can host web pages over the network. Apache is available within CentOS's default software repositories, which means you can install it with the dnf package manager.


To install Apache on CentOS:

1. Execute the command below to install the Apache package:

$ sudo dnf install httpd

After confirming the installation, dnf will install Apache and all required dependencies.

2. If you also plan to configure Apache to serve content over HTTPS, you will also want to open up port 443 by enabling the https service:

$ sudo firewall-cmd --permanent --add-service=https

3. Next, reload the firewall to put these new rules into effect:

$ sudo firewall-cmd --reload

After the firewall reloads, you are ready to start the service and check the web server.


To check your Apache Web Server:

1. Apache does not automatically start on CentOS once the installation completes, so you will need to start the Apache process manually:

$ sudo systemctl start httpd

2. Verify that the service is running with the following command:

$ sudo systemctl status httpd

You will receive an active status when the service is running.


To manage the Apache Process on CentOS:

Now that the service is installed and running, you can now use different systemctl commands to manage the service.

1. To stop your web server, type:

$ sudo systemctl stop httpd

2. To start the web server when it is stopped, type:

$ sudo systemctl start httpd

3. To stop and then start the service again, type:

$ sudo systemctl restart httpd

4. If you are simply making configuration changes, Apache can often reload without dropping connections. To do this, use this command:

$ sudo systemctl reload httpd

5. By default, Apache is configured to start automatically when the server boots. If this is not what you want, disable this behavior by typing:

$ sudo systemctl disable httpd

6. To re-enable the service to start up at boot, type:

$ sudo systemctl enable httpd

Apache will now start automatically when the server boots again.

Install Emacs Editor in Ubuntu 20.04 - How to perform it ?

This article covers methods to install Emacs editor in the Ubuntu 20.04 system. Emacs is a text editor designed for POSIX operating systems and available on Linux, BSD, macOS, Windows, and so on.


Emacs is an open-source, cross-platform editor that is highly customizable and provides a user-friendly interface to its users. 

It Provide features like multiple editing modes, full Unicode support for scripts, text manipulation tools, and integration with numerous external tools like the shell and git clearly gives an indication of how powerful it is.


To Install Emacs on Linux:

You can check if your Linux system has emacs installed by simply running the following command:

$ emacs

If you get an error message such as "-bash: -bash:: command not found", then you need to install it.

To install the emacs packages, run the command:

$ yum install emacs

On Ubuntu, execute:

$ apt-get install emacs


To install Emacs using Snap on Ubuntu:

Execute the following command in the command line:

$ sudo snap install emacs --classic

Once this is done, you can find Emacs in your list of installed applications.

Install Pepper Flash on Ubuntu 20.04 - How to do it ?

This article covers how to install the Pepper Flash plugin for the Mozilla Firefox browser on Ubuntu 20.04. After the successful installation of this plugin, we can easily use it for enjoying feature-rich content while browsing. 

We have also shared with you the method of removing this plugin from your system whenever you feel like it at the end of this guide.


How can I install Pepper Flash Player on Ubuntu? 

How can I setup Flash Player for Chromium web browser on Ubuntu?  

Pepper Flash Player is maintained by Google and is newer than Adobe Flash Player. 

Pepper Flash Player can be used with Chromium web browser.

The Pepper Flash Player is available on the Canonical Partners Repository. 

This repository is disabled by default on Ubuntu . 

1. Enable it by running the command:

$ sudo add-apt-repository "deb http://archive.canonical.com/ $(lsb_release -sc) partner"

2. Then, Update your package list after enabling the repository

$ sudo apt update

3. You can then install Pepper Flash Player in your Ubuntu 18.04 Desktop.

$ sudo apt -y install pepperflashplugin-nonfree

4. To update Pepperflash, use:

$ sudo update-pepperflashplugin-nonfree --install

5. After the installation of Pepper Flash Player on Ubuntu, make sure Flash is allowed to run in:

chrome://settings/content/flash

Install Mozilla Firefox on Ubuntu 20.04 - How to do it ?

This article covers how to install the Mozilla Firefox browser on the Ubuntu system. Mozilla Firefox is the official Internet browser for Ubuntu, therefore, most Ubuntu distros have it installed by default.

If your system lacks this browser due to any reason or if you have accidentally deleted it, we will tell you how to install it on your Ubuntu.


To update Firefox on Linux:

1. Click the menu button , click. Help and select About Firefox. On the menu bar click the Firefox menu and select About Firefox.

2. The About Mozilla Firefox Firefox window opens. Firefox will check for updates and download them automatically.

3. When the download is complete, click Restart to update Firefox.


To Delete Firefox and all it's data from Ubuntu:

1. run sudo apt-get purge firefox.

2. Delete /etc/firefox/ , this is where your preferences and user-profiles are stored.

3. Delete /usr/lib/firefox/ should it still be there.

4. Delete /usr/lib/firefox-addons/ should it still be there.

Install UrBackup Server and Client on Ubuntu 20.04 - How to do it ?

This article covers how to install and setup the UrBackup server on Ubuntu 20.04. Here, you will also learn how we can add a Linux host to be backed up. 

The main reason for data backup is to save important files if a system crash or hard drive failure occurs, you will lose your data. 

Therefore, a backup solution is much important for any data critical organization.

UrBackup is a free and powerful network backup solution for personal and enterprise. It has almost all features you need from a backup software. UrBackup supports Linux, Windows and Mac OS X.


Benefits of having UrBackup Server on your network are:

1. Centralized backup management

2. Supports multiple clients

3. Supports multiple simultaneous backups

4. Easy to restore


To Install client on Debian or Ubuntu:

1. Install the dependencies UrBackup needs: WxWidgets >= 2.9.0 On Debian/Ubuntu you can do that with apt or your favourite package manager:

$ apt install build-essential "g++" libwxgtk3.0-dev "libcrypto++-dev" libz-dev

2. Download the UrBackup client source files and extract them via e.g.

$ wget https://hndl.urbackup.org/Client/2.4.11/urbackup-client-2.4.11.tar.gz

$ tar xzf urbackup-client-2.4.11.tar.gz


3. Build the UrBackup client and install it:

$ cd urbackup-client-2.4.11

./configure

make -j4

sudo make install


4. Make sure that the UrBackup client backend runs correctly:

$ sudo urbackupclientbackend -v info


5. Start the UrBackup client backend on startup by adding it e.g. to rc.local:

$ sudo chmod +x /etc/rc.local

editor /etc/rc.local

Now add /usr/local/sbin/urbackupclientbackend -d before the exit 0.


6. Start the UrBackup client frontend and setup your paths by executing:

$ urbackupclientgui

and clicking on the tray icon and add paths. You can also do that on the server.


To Install UrBackup Client on Windows:

If you have a fully functioning UrBackup Server on Ubuntu, then you can install UrBackup client on client computers. For example, you can install UrBackup client on Windows 10.

1. Download UrBackup client for Windows 10: https://hndl.urbackup.org/Client/2.4.11/UrBackup%20Client%202.4.11.exe

2. After you install the client software on Windows 10, it will automatically search and connect to the UrBackup server. 

3. You will see the client computer listed on your UrBackup web administration console.

4. There will be an UrBackup icon in your taskbar where you can do several things such as:

i. Change settings

ii. Add/remote backup path

iii. Change component to backup

iv. See the status

Use Picture-in-Picture Mode in Google Chrome - How to do it ?

This article covers how to enable Picture-in-Picture mode (PiP) in the Google Chrome browser on Ubuntu 20.04. Users need to know notice that in case if they close their browser window, it will also close the smaller window. 

Also, you will learn how to disable the PiP mode in the Google Chrome browser.


How do I enable picture in picture on Chrome?

Here's how it works: open Chrome, go to a website that contains a video and play it fullscreen. 

From there, press the Home button to go to your Android Home Screen and the playing video will automatically transition to Picture-in-Picture. 

That's all!


What is picture in picture mode?

PIP is a special type of multi-window mode mostly used for video playback. 

It lets the user watch a video in a small window pinned to a corner of the screen while navigating between apps or browsing content on the main screen. 

Your app controls when the current activity enters PIP mode.

Assign Multiple IP Addresses to Single NIC in Linux Mint 20 - How to Do it ?

This article covers how to assign multiple IP addresses to a single interface in Mint OS. By following our guide carefully, you can either assign the IP address temporarily or permanently to your network interface.

NIC stands for network interface controller or network interface (controller) card. WNIC is wireless network interface controller or wireless network interface (controller) card. IP Addresses belong to network interfaces, not to the computer itself.


To Restart network service using command:

# systemctl restart network

To Verify the new IP address using command:

# ip addr


How configure multiple IP address in CentOS ?

Now, in order to add additional IP addresses you'll need to edit the configuration file (from hereon called “config file”) for this specific interface. On CentOS 7, the interface config files are located in /etc/sysconfig/network-scripts/ and they are all prefixed with ifcfg-.


How remove secondary IP address Linux?

To add or remove additional IP adresses and keep the configuration persistent, we need to Edit the corresponding /etc/sysconfig/network-scripts/ifcfg-eth[x] configuration file and add/remove as many additional IPADDR[n] and PREFIX[n] entries as additional IP addresses are required.


To configure a static IP address on CentOS  / RHEL :

1. Create a file named /etc/sysconfig/network-scripts/ifcfg-eth0 as follows:

DEVICE=eth0.

BOOTPROTO=none.

ONBOOT=yes.

PREFIX=24.

IPADDR=your_ip_address

2. Restart network service: systemctl restart network.


How do I login as a different user in Linux?

To change to a different user and create a session as if the other user had logged in from a command prompt, type "su -" followed by a space and the target user's username. Type the target user's password when prompted.


What is Nmcli in Linux?

nmcli is a command-line tool which is used for controlling NetworkManager. nmcli commnad can also be used to display network device status, create, edit, activate/deactivate, and delete network connections. Typical Uses: Scripts: Instead of manually managing the network connections it utilize NetworkMaager via nmcli.


Difference between the output of ifconfig and ipconfig:

Functionality: The ipconfig command displays all the currently connected network interfaces whether they are active or not. 

On the other hand, the ifconfig command displays only the enabled network interfaces that are connected to the system.

Install Spotify on Ubuntu 20.04 - Step by Step process to do it ?

This article covers the different methods of installation of Spotify on the Ubuntu 20.04 system. 

Spotify is a Popular music streaming application used globally and users can use any of the methods discussed above for its installation. 

The uninstallation process is also quite easy and we covered it for the ease of our readers. 

Users can also update Spotify with each newly released version.


Where is Spotify installed Linux?

If you followed the instructions on https://www.spotify.com/download/linux/ and installed from Ubuntu Software or snap, it should be located at /snap/bin/spotify . 

If you installed the debian package, it should be located at /usr/bin/spotify .


To update Spotify on Ubuntu:

1. Update list of available packages:

$ sudo apt-get update.

2. Install Spotify:

$ sudo apt-get install spotify-client.


To uninstall Spotify on Linux:

1. Quit Spotify.

2. Uninstall. sudo apt-get remove spotify-client.

3. Remove old config and cache.

cd $HOME/.config. rm -r spotify. cd $HOME/.cache. rm -r spotify.

4. Reinstall by following instructions on https://www.spotify.com/download/linux. 


To Install via command line on Ubuntu:

If you don't have access or don't want to use Ubuntu Software, it is possible to install Spotify from the command line with snap. 

Run the following command in your terminal:

$ snap install spotify

Install Tor Browser on Ubuntu 20.04 - Step by Step process to do it ?

This article covers how you can install the Tor browser on Ubuntu 20.04 Linux distribution. Now, you can use and do web browsing privately and in a secure way on your system. You can visit your local websites, your network service providers may block this browser.

When you use the Tor Browser, the connection to the website you are viewing is encrypted and protected from network surveillance and traffic analysis.


To Install Tor Browser Launcher on Ubuntu:

1. Add the Tor Browser Launcher PPA repository using the following command: 

$ sudo add-apt-repository ppa:micahflee/ppa.

2. Once the repository is enabled, update the apt package list and install the Tor Browser Launcher package by typing: 

$ sudo apt update 
$ sudo apt install torbrowser-launcher.


To uninstall Tor Kali Linux:

1. Locate your Tor Browser folder. On Linux, there is no default location, however the folder will be named "tor-browser_en-US" if you are running the English Tor Browser.

2. Delete the Tor Browser folder.

3. Empty your Trash.


To Update Tor Browser on Ubuntu ?

To help keep you secure, Tor Browser will automatically update itself when a new version is released.

Execute the following commands in your terminal:

$ sudo apt update
$ sudo apt install torbrowser-launcher

Install Zimbra Collaboration Suite (ZCS) on CentOS 8 - Step by step process to do it ?

This article covers how to install Zimbra mail server on CentOS & RHEL systems. Zimbra offers two editions, the commercially supported edition called 'Network Edition' & a free/open-source version called 'Open Source Edition'. 

Zimbra Collaboration Suite (ZCS) is a collaborative software suite that includes a mail & chat server with a web client.


Main components of Zimbra Mail and Collaboration Server are:

1. Zimbra Core: These are basic libraries, utilities, monitoring tools, and basic configuration files.

2. Zimbra LDAP: This has the OpenLDAP LDAP directory server that provides authentication and configs store for users and other zimbra components.

3. Zimbra MTA (mail routing server): Has Postfix mail transfer agent (MTA) that receives email via SMTP and routes each message to the appropriate Zimbra mailbox server using Local Mail Transfer Protocol (LMTP). It also includes the anti-virus and anti-spam components.

4. Zimbra Store (Zimbra server): The mailbox server includes Data store, Message store and Index store for the mailboxes on the server. When a mail arrives, the Zimbra server schedules a thread to have the message indexed in the index store.

5. Zimbra-SNMP: This is an optional component for for monitoring and it runs on every server (Zimbra server, Zimbra LDAP, Zimbra MTA). Swatch is used to watch the syslog output to generate SNMP traps.

6. Zimbra Logger: This is an optional component for the mailbox server. It installs tools for syslog aggregation, reporting, and message tracing. This is required for the message trace feature.


To Edit your hosts file on Ubuntu:

1. $ nano –w /etc/hosts

You should have this line

Ip_address server.domain.com server

Update it as per your server information.

2. Press ctrl key + o to save

3. Press ctrl key + x to exit

4. Restart your server to take effect all the changes

$ reboot


To install Zimbra on Ubuntu server:

1. Install Zimbra prerequisites

$ apt-get update 

$ apt-get install libgmp10 libperl5.18 libaio1 pax sysstat sqlite3

2. Download Zimbra Email Server

$ wget https://files.zimbra.com/downloads/8.6.0_GA/zcs8.6.0_GA_1153.UBUNTU14_64.20141215151116.tgz

3. Unpack the file

tar xzvf zcs-8.6.0_GA_1153.UBUNTU14_64.20141215151116.tgz

4. Go to Zimbra forder

cd zcs-8.6.0_GA_1153.UBUNTU14_64.20141215151116

5. Begin installation

./install.sh

NOTE : While running the install.sh command you will be prompted with the following questions.

Do you agree with the terms of the software license agreements? [N] Y

Install zimbra-ldap [Y] Enter

Install zimbra-logger [Y] Enter

Install zimbra-mta [Y] Enter

Install zimbra-dnscache [Y] N Enter

Install zimbra-snmp [Y] Enter

Install zimbra-store [Y] Enter

Install zimbra-apache [Y] Enter

Install zimbra-spell [Y] Enter

Install zimbra-memcached [Y] Enter

Install zimbra-proxy [Y] Enter

The System will be modified. Continue? [N] Y Enter

NOTE: Do not install dnscache because we already installed bind9.

Sometimes it takes for a while to install some packages.

You will receive this error:

DNS ERROR resolving server.domain.com server

Change hostname [Yes] Enter

Please enter the logical hostname for this host [server.domain.com] domain.com

Ports conflicts detected! – Press Enter /Return key to continue Enter

Setup a password for admin account.

Create and Run a Shell Script in CentOS 8 - Step by step process to do it ?

This article covers how to create and run a simple shell script in CentOS 8 system. With this, you can easily create and run even complex scripts and automate repetitive tasks. 

If you are using other Linux distributions, you can visit our posts on how to create and run a shell script in Ubuntu , Debian , and Linux Mint .


An SH file is a script programmed for bash, a type of Unix shell (Bourne-Again SHell). It contains instructions written in the Bash language and can be executed by typing text commands within the shell's command-line interface.


To write and execute a script:

1. Open the terminal. Go to the directory where you want to create your script.

2. Create a file with . sh extension.

3. Write the script in the file using an editor.

4. Make the script executable with command chmod +x <fileName>.

5. Run the script using ./<fileName>.

Change Date, Time, and Time Zone in CentOS 8 - How to do it ?

This article covers how you can easily adjust the time, date, and time zone of your system in CentOS 8.

To change the time zone in Linux systems use the sudo timedatectl set-timezone command followed by the long name of the time zone you want to set.


How to Synchronize Time on Installed Linux Operating Systems ?

1. On the Linux machine, log in as root.

2. Run the ntpdate -u <ntpserver> command to update the machine clock. For example, ntpdate -u ntp-time.

3. Open the /etc/ntp. conf file and add the NTP servers used in your environment.

4. Run the service ntpd start command to start the NTP service and implement you configuration changes.


Importance of man command in Linux:

man command in Linux is used to display the user manual of any command that we can run on the terminal. 

It provides a detailed view of the command which includes NAME, SYNOPSIS, DESCRIPTION, OPTIONS, EXIT STATUS, RETURN VALUES, ERRORS, FILES, VERSIONS, EXAMPLES, AUTHORS.

Install and Configure Apache Web Server with Virtual Host on Debian 10 - Do it now ?

This article covers how to perform installation and configuration of Apache web server on Debian 10.

Also, you will learn how to create virtual hosts on an Apache server and troubleshoot errors. These steps are almost the same for Ubuntu and LinuxMint distributions.

Apache HTTP Server is a free and open-source web server that delivers web content through the internet. It is commonly referred to as Apache and after development, it quickly became the most popular HTTP client on the web.


On most systems if you installed Apache with a package manager, or it came preinstalled, the Apache configuration file is located in one of these locations: /etc/apache2/httpd. conf. /etc/apache2/apache2.


Debian/Ubuntu Linux Specific Commands to Start/Stop/Restart Apache:

1. Restart Apache 2 web server, enter: # /etc/init.d/apache2 restart. $ sudo /etc/init.d/apache2 restart.

2. To stop Apache 2 web server, enter: # /etc/init.d/apache2 stop.

3. To start Apache 2 web server, enter: # /etc/init.d/apache2 start.


To check running status of LAMP stack:

1. For Ubuntu: # service apache2 status.

2. For CentOS: # /etc/init.d/httpd status.

3. For Ubuntu: # service apache2 restart.

4. For CentOS: # /etc/init.d/httpd restart.

5. You can use mysqladmin command to find out whether mysql is running or not.

Install Slack on CentOS 8 - Step by Step process to perform it ?

This article covers how you can easily install slack platform on your CentOS 8 Linux system through the command line. 

Using a slack application, team members of an organization can unify all conversations from different sources.


Slack is one of the most popular collaboration platforms in the world that brings all your communication together. 

Conversations in Slack are organized in channels. 

You can create channels for your teams, projects, topics, or any other purpose. 

You can search through everything that's been posted in channels or your messages. 

Slack also allows you to talk with your teammates over audio or video calls and share documents, images, videos, and other files.


To Install Slack on CentOS:

1. Update system

sudo yum -y update

2. Download and Install Slack on CentOS

sudo yum -y install wget

wget https://downloads.slack-edge.com/linux_releases/slack-3.4.0-0.1.fc21.x86_64.rpm

sudo  yum -y install https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm

sudo yum localinstall slack-3.4.0-0.1.fc21.x86_64.rpm

3. Start and Use Slack

Now that Slack is installed on your CentOS / RHEL 8 desktop, you can launch it through the command line,

$ slack

Find Files in Debian 10 - How to perform this ?

This article covers the different methods of finding files in Debian 10. 


To find a file in Debian:

Use the Locate command

1. Debian and Ubuntu sudo apt-get install locate.

2. CentOS yum install locate.

3. Prepare locate command for first use. To update the mlocate.db database before first use, run: sudo updatedb. 

To use locate, open a terminal and type locate followed by the file name you are looking for.


To locate a file in Linux:

1. find . - name thisfile.txt. If you need to know how to find a file in Linux called thisfile.

2. find /home -name *.jpg. Look for all . jpg files in the /home and directories below it.

3. find . - type f -empty. Look for an empty file inside the current directory.

4. find /home -user randomperson-mtime 6 -iname ".db".


To find packages in Debian:

You can also search for a package using the aptitude Ncurses user interface. 

1. Type 'aptitude' in the terminal and the following interface will be displayed in the window. 

2. To search for a package, press '/' and then type the package name into the search bar.


How to use grep to find a file?

The grep command searches through the file, looking for matches to the pattern specified. 

To use it type grep , then the pattern we're searching for and finally the name of the file (or files) we're searching in. 

The output is the three lines in the file that contain the letters 'not'.


To list files in Linux:

The easiest way to list files by name is simply to list them using the ls command. Listing files by name (alphanumeric order) is, after all, the default. 

You can choose the ls (no details) or ls -l (lots of details) to determine your view.


Which command have more searching options to search a file in file system in Linux?

Grep is a Linux / Unix command-line tool used to search for a string of characters in a specified file. The text search pattern is called a regular expression. 

When it finds a match, it prints the line with the result. 

The grep command is handy when searching through large log files.


grep is a command-line utility for searching plain-text data sets for lines that match a regular expression. 

Its name comes from the ed command g/re/p (globally search for a regular expression and print matching lines), which has the same effect.


To grep recursively in a directory:

To recursively search for a pattern, invoke grep with the -r option (or --recursive ). When this option is used grep will search through all files in the specified directory, skipping the symlinks that are encountered recursively.

Block or Unblock Ping Request on Debian 10 - How to perform this task ?

This article covers how you can block/unblock ping requests to your Debian system. You will learn different ways for blocking/unblocking ping requests either temporarily or permanently.


The --query-icmp-block=<type> option can be used to determine if a type is confgured to allow or deny. 

The --add-icmp-block=<type> option can be used to block a certain type. 

The --remove-icmp-block=<type> option can be used to not block a certain type. 

After adding or removing a block, reload the firewall.


To block ping requests in Linux:

1. Edit /etc/sysctl.conf. Add the following line to your /etc/sysctl.conf : net.ipv4.icmp_echo_ignore_all=1. Then: sysctl -p.

2. Using iptables: iptables -I INPUT -p icmp --icmp-type echo-request -j DROP.

3. With cron. Run crontab -e as root, then add the following line: @reboot echo "1" > /proc/sys/net/ipv4/icmp_echo_ignore_all.


To block ping in iptables:

1. Add a rule that tells the iptables firewall to block ping in and out of a server by controlling the ICMP requests.

2. Remove the rule that tells the iptables firewall to allow ping in and out of a server by controlling the ICMP requests.


To enable ping on Linux server?

# iptables -D INPUT -p icmp --icmp-type echo-request -j REJECT D : 

This command switch is used to delete the rule. Once the ping enabled, the server should now respond to ping requests

Create and Run a Shell Script in Linux Mint 20 - Step by Step process to perform this ?

This article covers the method of creating and running a shell script in Linux Mint 20.

With this, you can write and execute complex shell scripts in Linux Mint 20 very easily.


To write and execute a script:

1. Open the terminal. Go to the directory where you want to create your script.

2. Create a file with . sh extension.

3. Write the script in the file using an editor.

4. Make the script executable with command chmod +x <fileName>.

5. Run the script using ./<fileName>.


To save a .sh file in Ubuntu:

1. Run nano hello.sh.

2. nano should open up and present an empty file for you to work in.

3. Then press Ctrl-X on your keyboard to Exit nano.

4. nano will ask you if you want to save the modified file.

5. nano will then confirm if you want to save to the file named hello.sh.


To Make a Bash Script Executable in Linux:

1) Create a new text file with a . sh extension.

2) Add #!/bin/bash to the top of it. This is necessary for the “make it executable” part.

3) Add lines that you'd normally type at the command line.

4) At the command line, run chmod u+x YourScriptFileName.sh.

5) Run it whenever you need!

Install Opera Browser on CentOS 8 - Step by step process to perform it ?

This article covers how to install the Opera browser using different ways on CentOS 8. We have also shown how you can install packages by using the wget command. Opera browser is amazing on your CentOS 8 system.


To install Opera browser on CentOS:

1. Add Opera YUM repository

Run the following commands to manually add the Opera RPM repository to your RHEL / CentOS 8 system.

$ sudo tee /etc/yum.repos.d/opera.repo <<RPMREPO

[opera]

name=Opera packages

type=rpm-md

baseurl=https://rpm.opera.com/rpm

gpgcheck=1

gpgkey=https://rpm.opera.com/rpmrepo.key

enabled=1

RPMREPO

2. Install Opera Browser on RHEL 8 / CentOS 8

Use yum package manager command to install Opera Browser on RHEL 8 / CentOS 8.

$ sudo yum -y install opera-stable

3. Wait for the installation to complete then launch the browser from the CLI:

$ opera 

Create and Run a Perl Script in Linux Mint - How to perform this task ?

This article covers how to create and execute a Perl script in Linux Mint 20. Moreover, if Perl is not installed on your system already, then we have even shared with you the method of installing it on your system and also ensuring if its interpreter exists there or not.

Perl is a programming language that can be used to perform tasks that would be difficult or cumbersome on the command line. Perl is included by default with most GNU/Linux distributions. 

PERL- Practical Extraction and Reporting Language (not an official acronym), is a stable and cross-platform language and was created by Larry Wall. 

Perl is an open source, general-purpose, interpreted language. Programs written in Perl are called Perl scripts. 

Perl supports both Procedural language and Object Oriented language and has powerful built-in support for text processing and have a collection of third-party modules. Perl language is mainly used for Web Applications, System Administration, Batch Processing, Applications which involving text processing and most command line applications. 


To run a Perl script in Unix:

1. Find the interpreter/executors path. In this case its /usr/bin/perl or /usr/bin/env perl.

2. Add it to the first line of the file as #!/usr/bin/perl .

3. Give execute permission to the file chmod +x example.pl.


Features of Perl language:

1. Perl takes the best features from other languages, such as C, awk, sed, sh, and BASIC, among others.

2. Perls database integration interface DBI supports third-party databases including Oracle, Sybase, Postgres, MySQL, and others.

3. Perl works with HTML, XML, and other mark-up languages.

4. Perl supports Unicode.

5. Perl supports both procedural and object-oriented programming.

6. Perl interfaces with external C/C++ libraries through XS or SWIG.

7. Perl is extensible.

8. The Perl interpreter can be embedded into other systems.


To install Perl in Linux:

1. Before proceeding with the installation of Perl in your Linux system, please have a check Perl is installed or not on your Linux system by running the below command:

# perl -v

2. Download the zipped source code available for Unix/Linux by running the below command:

# wget https://www.cpan.org/src/5.0/perl-5.28.1.tar.gz

3. After download the zip file runs the below commands to extract and install Perl:

# tar -xzf perl-5.28.1.tar.gz

# cd perl-5.28.1

# ./Configure -de

#make

# make test

# make install


How to write your Perl script in Linux?

You can write your Perl script in a text file and the text file should have the extension '.pl'. 

To run your Perl script run the below command.

#perl filename

Eg: #perl hello.pl

Configure NFS Server and Client on Linux Mint 20 - Step by Step process to do it ?

This article covers how to setup the NFS server and client on Mint. You will learn how to install the NFS server and client, configure and share NFS export directories, and mount/unmount the NFS shares on the client.

Network File System (NFS), is a distributed file system that allows various remote systems to access a file share. We all know that files should be stored on a central server for security and ease of backup. NFS provides us with a file sharing service that is easily managed and controls client access to resources.


To Install the NFS Client on the Client Systems:

1. Install the NFS-Common Package. As is the norm, begin by updating the system packages and repositories before anything else.

2. Create a NFS Mount Point on Client.

3. Mount NFS Share on Client System.

4. Testing the NFS Share on Client System.


A Network File System (NFS) allows remote hosts to mount file systems over a network and interact with those file systems as though they are mounted locally. This enables system administrators to consolidate resources onto centralized servers on the network.


Benefits of setting up an NFS server:

1. Enables multiple computers to use the same files, so everyone on the network can access the same data.

2. Reduces storage costs by having computers share applications instead of needing local disk space for each user application.

Install Opera Web Browser on Ubuntu 20.04 - Step by Step process to perform it ?

This article covers how to install Opera web browser on an Ubuntu 20.04 system. Opera web browser provides its unique features and has many users all over the world.

Users can access and then use the Opera browser once they have installed it in their systems. You will also learn how to uninstall the browser from the Ubuntu 20.04 system.


To install Opera browser on Linux:

1. Add Opera browser Repository. Let's start by adding an Opera repository and keyring.

2. Install Opera Browser. At this stage to install the Opera browser on Ubuntu 18.04 Bionic Beaver is easy as executing the below command: $ sudo apt install opera-stable.

3. Start Opera Browser.


To Install Google Chrome on Debian:

1. Download Google Chrome. Open your terminal either by using the Ctrl+Alt+T keyboard shortcut or by clicking on the terminal icon.

2. Install Google Chrome. Once the download is complete, install Google Chrome by typing: $ sudo apt install ./google-chrome-stable_current_amd64.deb.


To start Chrome on Linux:

1. Edit ~/. bash_profile or ~/. zshrc file and add the following line alias chrome="open -a 'Google Chrome'"

2. Save and close the file.

3. Logout and relaunch Terminal.

4. Type chrome filename for opening a local file.

5. Type chrome url for opening url.


To install Google Chrome on Linux Mint:

1. Add this link to the list of repo sources "deb http://dl.google.com/linux/chrome/deb/ stable main"

2. Run in terminal "sudo apt-get update"

3. Run in terminal "sudo aptitude install google-chrome-stable"


The sudo apt-get update command is used to download package information from all configured sources.

So when you run update command, it downloads the package information from the Internet. It is useful to get info on an updated version of packages or their dependencies.


To Uninstall Opera on Ubuntu:

1. In order to uninstall Opera through the command line, enter the following

$ sudo apt-get remove opera-stable

2. The repository you added will still be residing on your system. Enter the following command in order to remove it:

$ sudo apt-delete-repository "deb [arch=i386,amd64] https://deb.opera.com/opera-stable/ stable non-free

Free Up Disk Space in Ubuntu 20.04 LTS - How to do this ?

This article covers different effective ways to free up some disk space on your Ubuntu system or other Linux distro. 

Although Linux does not clutter up like Windows, it may be useful to occasionally clean up Linux. Especially in systems with a smaller hard drive it can be beneficial to clean Linux. Occasionally cleaning up Linux does have to be done on a daily basis or weekly basis, 1 time per month is more than sufficient.


Terminal commands to free up some disk space on your Linux System:

There are 3 terminal commands which you can use top clean up Linux Mint. 

Each terminal will be explained about what they do and remove. 

All three commands contribute to free up disk space.

1. sudo apt-get autoclean

This terminal command deletes all .deb files from /var/cache/apt/archives. It basically cleans up the apt-get cache.

2. sudo apt-get clean

This terminal command is used to free up the disk space by cleaning up downloaded .deb files from the local repository.

3. sudo apt-get autoremove

This terminal command used to remove packages that were automatically installed to satisfy dependencies for some package and no longer needed by those packages.

Install Wine on CentOS 8 - Step by Step process to do it ?

This article covers how to install Wine on CentOS 8. With the use of this package, you can easily use the native Windows applications on CentOS 8. However, you can also remove this package from your CentOS 8 system to conserve the memory whenever you want.


How to Install Wine 4 on CentOS 8:

Install EPEL Repos on CentOS 8

Wine is not included in the default CentOS 8 repositories but however available on EPEL repos. Therefore, run the command below to install EPEL repos:

$ dnf install https://dl.fedoraproject.org/pub/epel/epel-release-latest-8.noarch.rpm


To run Wine on CentOS 8:

Wine command takes the following syntax.

$ wine program [arguments]

To obtain help on Wine usage;

$ wine --help

Consult man pages for Wine for more insight.

$ man wine

Before you can use Wine to run Windows applications, reboot your system to setup the Wine environment.

$ systemctl reboot

5 Key Google Chrome Extensions

This article covers the key Google Chrome extensions which will definitely enhance your browsing experience and will make Google Chrome even more helpful and useful for you. Google Chrome extensions are programs that can be installed into Chrome in order to change the browser's functionality.

Adding to do lists or notes to Chrome. Password management. Making it easier to copy text from a site. Protect your privacy and making web browsing more secure.

Some extensions can be ethically dubious or even malicious, but Chrome features new restrictions on extension developers that should help mitigate that problem.

Unzip Files in Linux - How to perform it ?

This article covers how to use the unzip command on the CentOS 8 Linux system.

Also, you will learn various uses of the unzip command through which you can list ZIP archive content and extract files. You can utilize the unzip command according to your needs.


How to Create a ZIP File with the zip Command ?

To create a ZIP file, you need to tell zip the name of the archive file and which files to include in it. 

You don't need to add the ".zip" extension to the archive name, but it does no harm if you do.

To create a file called source_code.zip containing all the C source code files and header files in the current directory, you would use this command:

$ zip source_code *.c *.h


How to Unzip a ZIP File With the unzip Command ?

To extract the files from a ZIP file, use the unzip command, and provide the name of the ZIP file. 

Note that you do need to provide the ".zip" extension.

$ unzip source_code.zip


To Unzip on the Linux command line:

The simplest option that will extract the contents to current directory:

$ unzip backup.zip


To change the target directory for extracted material, use -d option followed by the desired directory:

$ unzip backup.zip -d ./restore-directory


To preview contents of zip file:

$ unzip -l backup.zip


If you don't want to unzip the whole file, then add the specific files to extract at the end:

$ unzip backup.zip file1 subdirectory/file2


The inverse of the above command. Unzip every file EXCEPT the ones specified after the -x modifier:

$ unzip backup.zip -x file1 subdirectory/file2


Unzipping a password protected file:

$ unzip -p mypassword backup.zip

Install and Run Python on CentOS 8 - How to do it ?

This article covers how to install python2 and python3 on CentOS 8. By default, python2 and python3 are not installed on CentOS 8. To install both, you need to install all python packages separately according to python versions. Also, you can run python2 and python3 environments on your system. 

The 'alternatives --auto python' command is used to set any python version as the default. 


To run Python in Linux:

A widely used way to run Python code is through an interactive session. 

To start a Python interactive session, just open a command-line or terminal and then type in python, or python3 depending on your Python installation, and then hit Enter .


Python comes preinstalled on most Linux distributions, and is available as a package on all others. 

However there are certain features you might want to use that are not available on your distro's package. 

You can easily compile the latest version of Python from source.


Installing Python 3 on Linux:

1. To see which version of Python 3 you have installed, open a command prompt and run

$ python3 --version

2. If you are using Ubuntu 16.10 or newer, then you can easily install Python 3.6 with the following commands:

$ sudo apt-get update

$ sudo apt-get install python3.6

3. If you're using another version of Ubuntu (e.g. the latest LTS release) or you want to use a more current Python, we recommend using the deadsnakes PPA to install Python 3.8:

$ sudo apt-get install software-properties-common

$ sudo add-apt-repository ppa:deadsnakes/ppa

$ sudo apt-get update

$ sudo apt-get install python3.8

4. If you are using other Linux distribution, chances are you already have Python 3 pre-installed as well. If not, use your distribution's package manager. For example on Fedora, you would use dnf:

$ sudo dnf install python3


To see if pip is installed, open a command prompt and run:

$ command -v pip

Reboot Linux Mint 20 - How to do it ?

This article covers methods to reboot the Linux Mint. If you want to shut down your Linux Mint instead of rebooting, Learn How to Shutdown Linux Mint 20 .

Rebooting is the same as restarting, and close enough to powering off and then turning off your device. The purpose is to close and reopen the operating system. Resetting, on the other hand, means taking the device back to the state in which it left the factory. Resetting wipes all your personal data.


The systemctl command accepts, among many other options, halt (halts disk activity but does not cut power) reboot (halts disk activity and sends a reset signal to the motherboard) and poweroff (halts disk acitivity, and then cut power). These commands are mostly equivalent to starting the target file of the same name.


To reboot Linux:

1. To reboot the Linux system from a terminal session, sign in or "su"/"sudo" to the "root" account.

2. Then type " sudo reboot " to reboot the box.

3. Wait for some time and the Linux server will reboot itself.


To shut down Linux Mint:

Execute the following command:

sudo chmod u+s /sbin/shutdown

You will be prompted for your root password. After that, you're done and can type "exit" to exit out of the Terminal.


Linux Commands to Shutdown and Reboot the System:

1. Linux shutdown / reboot command. On Linux, like all tasks, the shutdown and restart operations can also be done from the command line.

2. "shutdown" command.

3. "reboot" command.

4. "halt" command.

5. "poweroff" command.

6. REISUB - R E I S U B key strokes.

Modify Date, Time, and Timezone in Debian 10 - How to do it ?

This article covers how you can easily change the date, time, and timezone in your Debian system. To change your Debian system's timezone, run the sudo timedatectl set-timezone command followed by the long name of the time zone you want to set

Based on your convenience, you can either choose the command line or the GUI method. If you are using Ubuntu OS, you can visit our post on How to Change the Date, Time, and Timezone in Ubuntu 20.04 LTS .


Using the correct timezone is essential for many systems related tasks and processes. 

For example, the cron daemon uses the system's timezone for executing cron jobs, and the timestamps in the log files are based on the same system's timezone.

On Debian, the system's timezone is set during the install, but it can be easily changed at a later time.


To check the Current Timezone:

timedatectl is a command-line utility that allows you to view and change the system's time and date. It is available on all modern systemd-based Linux systems:

$ timedatectl


To modify Change Time Zone in Debian 10 / Debian 9:

1. Using /etc/localtime File. In this method, we will use /etc/localtime (link to the original time zone file) file to set the timezone for your system.

2. Using timedatectl command. In this method, we will use the timedatectl command to change the time zone in Debian.

Install Chrony on Linux Mint - Easy steps to do it ?

This article covers how to #install Chrony on Linux Mint 20. Once it will be installed on your system, its daemon will silently work in the background to synchronize your system's clock with the #NTP server. 

However, if you do not want Chrony to perform this job any longer, then you can simply uninstall it as well.

Chrony is a flexible implementation of the Network Time Protocol (NTP). 

It is used to synchronize the system clock from different NTP servers, reference clocks or via manual input.


Chrony comes with two programs:

1. chronyc – command line interface for chrony

2. chronyd – daemon that can be started at boot time


How to Install #Chrony in #Linux :

On some systems, chrony may be installed by default. Still if the package is missing, you can easily install it. 


You can install chrony Using your default package manager tool on your respective Linux distributions using following command:

# yum -y install chrony    [On CentOS/RHEL]

# apt install chrony       [On Debian/Ubuntu]

# dnf -y install chrony    [On Fedora 22+]


To check the status of chronyd use the following command:

# systemctl status chronyd      [On SystemD]

# /etc/init.d/chronyd status    [On Init]


If you want to enable chrony daemon upon boot, you can use the following command:

# systemctl enable chronyd       [On SystemD]

# chkconfig --add chronyd        [On Init]


How to Check Chrony Synchronization in Linux ?

To check if chrony is actually synchronized, we will use it's command line program chronyc, which has the tracking option which will provide relevant information:

# chronyc tracking


To check information about chrony’s sources, you can issue the following command:

# chronyc sources

Install and Use TermRecord on CentOS 8 - Do it now

This article Covers how to install the TermRecord application on CentOS 8. The TermRecord application allows you to better enjoy the recorded #Terminal content. 

TermRecord is a simple, open source, terminal session recorder with easy-to-share self-contained HTML output.

#TermRecord Stores these files as your own notes, email them to collaborators, use them as instructional examples, or whatever you wish.

TermRecord consumes output from the script command with timing information and can create a self-contained HTML file which replays the recorded session without needing to load anything from the web. 

These term sessions can be emailed and viewed on practically any device (including iPads etc.). 

The end user only needs a modern browser.


Features of TermRecord includes:

1. User friendly.

2. Detects the terminal size.

3. Nest sessions.

4. Cross-platform HTML-based output.

5. Stores the output as either JSON, embeddable JavaScript, or a static HTML file.

6. Written in Python.


To install on TermRecord #CentOS:

1. First of all, connect to your server via SSH and make sure that all of your system software is up to date. 

Run the following command to update the package list and upgrade all of your system software to the latest version available:

$ sudo yum update -y

2. Install Pip. 

Add the EPEL Repository:

$sudo yum install epel-release

Install pip:

$ sudo yum install python-pip

Once the installation has completed, you can verify that it was successful by using the following command:

$pip -V

3. Install TermRecord

Install TermRecord using the Python package manager (pip):

$sudo pip install TermRecord


How to use TermRecord on CentOS system ?

Taking a video of the terminal with TermRecord is rather simple, just run the following command (be attentive to capital letters):

TermRecord -o record.html

Note: We specify the output file in which the video will be recorded using the -o option. the .html format is the default format.

For more complex operations check out TermRecord --help

Assign Multiple IP Addresses to Single NIC in Debian 10 - How to do it ?

This article covers how to assign and remove multiple IP addresses to and from a single NIC. Based on your preferences, you can either assign the multiple IP addresses temporarily or permanently.

There's no simple command that you can run to determine whether the IP address on a Linux system is assigned by DHCP or static. 

If it changes when the system restarts, it's clearly dynamically assigned, but even a dynamic address has some resistance to change. 

The best way is to look at the configuration file.


To add a static route in Linux:

1. Use the route command with the –p option to add a persistent route: # route -p add default ip-address.

2. Use the route command with the –name option to add a persistent route by specifying a name rather than destination and gateway: # route -p add destination-address gateway-address -name name.


What is ip route command in Linux?

ip route is used to manipulate entries in the kernel routing tables. 

Route types: 

1. unicast - the route entry describes real paths to the destinations covered by the route prefix. 

2. unreachable - these destinations are unreachable. 

Packets are discarded and the ICMP message host unreachable is generated.

Create and Run a Shell Script in Debian 10 -Step by step process to do it ?

This article covers how to easily create a shell script and automate repetitive jobs in #Linux. Shell scripts are just a series of commands that you add in a file and run them together.  


To write and execute a #script:

1. Open the #terminal. Go to the directory where you want to create your script.

2. Create a file with . sh extension.

3. Write the script in the file using an editor.

4. Make the script executable with command chmod +x <fileName>.

5. Run the script using ./<fileName>.


#Shell is a #UNIX term for an interface between a user and an operating system service. 

Shell provides users with an interface and accepts human-readable commands into the system and executes those commands which can run automatically and give the program's output in a shell script.

Different Methods to Find Your Private IP Address in Linux Mint 20 ?

This article covers different methods to quickly find the IP address of your #Linux Mint system. 

The simplest way to check the ip address of linux Mint, when using the bash shell is typing the command ifconfig. 

On typing the ifconfig you will not only be provided with the ip address, but also the mac address, subnet mask and other information. 


The following commands will get you the private IP address of your interfaces:

1. ifconfig -a.

2. ip addr (ip a).

3. hostname -I | awk '{print $1}'.

4. ip route get 1.2.

5. nmcli -p device show.


What is the #ipconfig command for Linux?

ifconfig(interface configuration) command is used to configure the kernel-resident network interfaces. It is used at the boot time to set up the interfaces as necessary. 

After that, it is usually used when needed during debugging or when you need system tuning.

Install PostgreSQL in CentOS 8 - Step by Step Process ?

This article will cover how to install and remove the PostgreSQL server and create a database in PostgreSQL on CentOS 8. Also you will learn how to add tables in the database by using the SQL query.

PostgreSQL is available from CentOS 8's default AppStream software repository, and there are multiple versions which you can install. 

You can choose between these versions by enabling the appropriate collection of packages and dependencies that align with the version you want to install, with each collection referred to as a module stream.


To List out the available streams for the postgresql module using the dnf command:

$ dnf module list postgresql

Reboot Debian 10 - Different methods to do it ?

This article covers different methods to reboot your Debian 10 system. reboot command is used restart or reboot the system.
In a Linux system administration, there comes a need to restart the server after the completion of some network and other major updates.
It can be of software or hardware that are being carried on the server.

To reboot Linux using the command line:
1. To reboot the Linux system from a terminal session, sign in or “su”/”sudo” to the “root” account.
2. Then type “ sudo reboot ” to reboot the box.
3. Wait for some time and the Linux server will reboot itself.

To restart a Linux (Ubuntu / Debian) network?
1. Use the following command to restart the server networking service. # sudo /etc/init.d/networking restart or # sudo /etc/init.d/networking stop # sudo /etc/init.d/networking start else # sudo systemctl restart networking.
2. Once this done, use the following command to check the server network status.

Install MongoDB on Debian 10 - Step by step process to do it ?

This article covers how to #install / #uninstall MongoDB on your Debian system. You have also learned how to manage MongoDB services.
MongoDB is an opensource, cross-platform NoSQL database server.
In MongoDB, data is stored in flexible, JSON-like documents where fields can vary from document to document.
It does not require a predefined schema, and data structure can be changed over time.

To install MongoDB on #Debian:
Perform the following steps as root or user with sudo privileges to install MongoDB on a Debian system.
1. Install the packages required for adding a new repository:

$ sudo apt install dirmngr gnupg apt-transport-https software-properties-common ca-certificates curl

2. Add the MongoDB GPG key to your system:

$ curl -fsSL https://www.mongodb.org/static/pgp/server-4.2.asc | sudo apt-key add -

3. Enable the MongoDB repository:

$ sudo add-apt-repository 'deb https://repo.mongodb.org/apt/debian buster/mongodb-org/4.2 main'

4. Packages with older versions of MongoDB are not available for Debian 10.
Update the packages list and install the mongodb-org meta-package:

$ sudo apt update
$sudo apt install mongodb-org


The following packages will be installed on the system as a part of the mongodb-org package:
mongodb-org-server - The mongod daemon and corresponding init scripts and configurations.
mongodb-org-mongos - The mongos daemon.
mongodb-org-shell - The mongo shell is an interactive JavaScript interface to MongoDB. It is used to perform administrative tasks through the command line.
mongodb-org-tools - Contains several MongoDB tools for importing and exporting data, statistics, as well as other utilities.

To Start the #MongoDB service and enable it to start on boot:

sudo systemctl enable mongod --now

Install Google Chrome on Linux Mint 20 - Step by step process to do it ?

This article covers different methods to #install Google Chrome on Linux Mint. You can easily install/uninstall Google Chrome on Linux mint 20 OS. You will also learn how to set Google Chrome as the default web browser so that all your links or URLs open by default in Google Chrome.

You can install Google #Chrome onto your Linux #Mint 20 distro by using either of the following two methods:
1. Install Chrome by adding the Google Chrome repository.
2. Install Chrome using the . deb package.

To install #Google Chrome on #Linux Mint:
1. Add this link to the list of repo sources "deb http://dl.google.com/linux/chrome/deb/ stable main"
2. Run in terminal "sudo apt-get update"
3. Run in terminal "sudo aptitude install google-chrome-stable"

Running sudo apt-get update (or sudo aptitude update ) updates this on your local system.
This is the step that actually retrieves information about what packages can be installed, including what updates to currently installed packages packages are available, from Internet sources.

Install Wine on Ubuntu 20.04 LTS - Step by step process to do it ?

This article covers how to install Wine on Ubuntu 20.04. We used the WineHQ repositories and downloaded them directly for their installation.
Users can use it now for running all Windows-based applications.

To Install Wine from a Standard Ubuntu Repository (recommended):
We recommend that you install Wine on your system through the standard Ubuntu repository, as this way you can have a more stable version on your system.
1. Run the following command in the Terminal as a root user in order to install Wine on a 64-bit version of Ubuntu:
$ sudo apt install wine64
2. Please enter y when you are prompted with a y/n option for installation.
After that, the Wine application will be installed and ready for use.
3. For a 32-bit Ubuntu system, you can use the following command:
$ sudo apt install wine32
4. You can verify the version of Wine through the following command:
$ wine --version

To Install Wine without Internet:
To install Wine on an Ubuntu machine without internet access, you must have access to a second Ubuntu machine (or VM) with an internet connection to download the Wine .deb package and its dependencies.
On the machine with internet, add the WineHQ repository and run apt update.
Next, cache just the packages necessary for installing wine, without extracting them:
sudo apt-get clean
sudo apt-get --download-only install winehq-devel
sudo apt-get --download-only dist-upgrade

Copy all of the .deb files in /var/cache/apt/archives to a USB stick:
cp -R /var/cache/apt/archives/ /media/usb-drive/deb-pkgs/

Finally, on the machine without internet, install all of the packages from the flash drive:
cd /media/usb-drive/deb-pkgs
sudo dpkg -i *.deb

Install Google Chrome on Debian 10 - How to do it ?

This article covers different methods to install and enjoy Google Chrome on your Debian 10 system. Moreover, whenever you feel like you do not need this browser any longer, then we have even explained to you the method of removing this browser from your Debian 10 system for your convenience.


To Install Google Chrome on Debian:

1. Downloading Google Chrome. Open the terminal either by using the Ctrl+Alt+T keyboard shortcut or by clicking on the terminal icon.

2. Installing Google Chrome. Once the download is complete, install Google Chrome with apt : sudo apt install ./google-chrome-stable_current_amd64.deb.

Install MariaDB on Ubuntu 20.04 LTS - Step by step process to do it ?

This article covers how to install MariaDB on Ubuntu 20.04 LTS system. Also you will learn how to secure it by configuring some security options and then, in the end, we have tested the connection to MariaDB. The #Ubuntu server should have a non-root administrative user and a firewall configured with UFW.

By following the above simple steps, you can easily setup MariaDB on your ubuntu system. 

For more information, visit MariaDB's official documentation .

MariaDB is one of the most widely used and open-source database management systems. 

MariaDB is considered as a replacement for #MySQL and has much more features and capabilities that you cannot find in MySQL.


To install #MariaDB on Debian:

1. Update your package index using apt;

$ sudo apt update

2. Install the mariadb-server package using apt. The package also pulls in related tools to interact with MariaDB;

$ sudo apt install mariadb-server

3. Run the included mysql_secure_installation security script to restrict access to the server;

$ sudo mysql_secure_installation

Methods to Install Google Chrome on CentOS 8 ?

This article covers the different methods for the installation of Google Chrome on the CentOS 8 system using the terminal commands and graphical method. 

Once the installation of chrome is complete, now you can feel free to add chrome extensions and favorite themes from the web store of Google Chrome.


To install Google Chrome 78 on a RHEL/CentOS/Fedora Linux:

1. Open the Terminal application. Grab 64bit Google Chrome installer.

2. Type the following command to download 64 bit version of Google Chrome:

wget https://dl.google.com/linux/direct/google-chrome-stable_current_x86_64.rpm

3. Install Google Chrome and its dependencies on a CentOS/RHEL, type:

sudo yum install ./google-chrome-stable_current_*.rpm

4. Start Google Chrome from the CLI:

google-chrome &


To upgrade Google Chrome from an older version:

You can simply update it by typing the following yum command:

$ sudo yum update google-chrome-stable

OR use the following dnf command to update it on a Fedora Linux:

$ sudo dnf update google-chrome-stable


To uninstall Chrome from Ubuntu:

1. Open the Terminal: It should be present on your desktop or taskbar.

2. Type sudo apt-get purge google-chrome-stable and press Enter to uninstall the Chrome browser.

3. Type sudo apt-get autoremove and press Enter to clean up the Package Manager to ensure that there are no lingering files.

Job for mariadb.service failed because the control process exited with error code - How to fix it ?

This article covers how to resolve the above maiadb problem "Job for mariadb.service failed because the control process exited with error code" which may arise during the installation of #MariaDB on #CentOS 8.

The /var/lib/mysql directory is not empty when MariaDB is installed, it contains e.g. the 'mysql' database and some other files. 

Recreating the folder, even with correct permissions, will not help you. 

Either MariaDB has not been successfully installed or the directory was removed. Reinstall MariaDB to get a working basic database system back.

Also, you can give access /var/log/mysql/* to mysql by running the command:

sudo chown mysql:mysql /var/log/mysql/*


MariaDB offers more and better storage engines, NoSQL support, provided by Cassandra, allows you to run SQL and NoSQL in a single database system. 

MariaDB also supports TokuDB, which can handle big data for large organizations and corporate users.


To view mysql error logs:

1. edit /etc/my.cnf [mysqld] log=/tmp/mysql.log.

2. restart the computer or the mysqld service service mysqld restart.

3. open phpmyadmin/any application that uses mysql/mysql console and run a query.

4. cat /tmp/mysql.log ( you should see the query )

Install PostgreSQL on Debian 10 - Step by step process to do it ?

This article will guide you on how you can install PostgreSQL #DBMS on your Debian 10 system. Also, we also shared with you the method with which you can remove the PostgreSQL DBMS from your #Debian 10 system.

#PostgreSQL supports transaction s, subselects, trigger s, view s, foreign key referential integrity, and sophisticated locking.


pgAdmin is the de facto GUI tool for PostgreSQL, and the first tool anyone would use for PostgreSQL. It supports all PostgreSQL operations and features while being free and open-source. With pgAdmin you can Create, view and edit on all common PostgreSQL objects.

#PgAdmin is graphical user interface administration tool for PostgreSQL. It does not include a PostgreSQL database server.


To install PostgreSQL 9.5 on #Ubuntu:

1. sudo apt-get update.

2. sudo apt-get install postgresql postgresql-contrib.

3. sudo -u postgres psql.

4. # Replace xxxxxxx with your own password ALTER USER postgres WITH ENCRYPTED PASSWORD 'xxxxxxx';

5. # Feel free to replace nano with an editor of your choice sudo nano /etc/postgresql/9.5/main/pg_hba.conf.


ANALYZE in #Postgres collects statistics about the contents of tables in the database, and stores the results in the pg_statistic system catalog. Subsequently, the query planner uses these statistics to help determine the most efficient execution plans for queries.

Install MariaDB on CentOS 8 - Step by step process ?

This article will guide you on how to install MariaDB on your CentOS 8 system. Now you can create new databases and grant privileges to other database users. Also, you can add users and create new databases for web or desktop applications which will be written in PHP, Python, and so on.

In MariaDB replication is faster whereas in MySQL replication is slower. 

MariaDB is Open Source whereas MySQL uses some proprietary code in its Enterprise Edition. 

MariaDB doesn't support Data Masking and Dynamic column while MySQL supports it. Comparatively MariaDB is faster than MySQL.


To uninstall MariaDB and install mysql:

1. Purge mariadb sudo apt purge mariadb-* Remove all databases ('Yes' answer)

2. Purge mysql sudo apt purge mysql-*

3. Remove folders: sudo rm -r /usr/share/mysql/ sudo rm -r /etc/mysql/ sudo rm -r /lib/systemd/system/mysql.service.

4. Now you can try to install oracle mysql: sudo apt install mysql-server.

Install Wine on Debian 10 - Step by step process ?

This article will guide you on steps to install Wine on Debian via WineHQ repository. Also you will learn how to uninstall it from your system if you no longer need it. 

For official documentation, you can visit Wine for Debian.

If you are working on Linux Mint OS, visit our post on How to Install Wine on Linux Mint 20 .


Wine stands for Wine Is Not an Emulator. While a virtual machine or emulator simulates internal Windows logic, Wine translates those Windows logic to native UNIX/POSIX-complaint logic. 

In simple and non-technical words, Wine converts internal Windows commands to commands your Linux system can natively understand.


To Check Wine Version:

Wine installation successfully completed. 

Use the following command to check the version of wine installed on your system

wine --version 


A Linux repository is a storage location from which your system retrieves and installs OS updates and applications. 

Each repository is a collection of software hosted on a remote server and intended to be used for installing and updating software packages on Linux systems.

Repositories contain thousands of programs.

Process to configure an NTP server and client on Ubuntu 20.04 LTS ?

This article will guide you on how to configure the NTP server on the #Ubuntu machine and then sync a clock of NTP client machine. Now you can easily set up NTP server and connect multiple client machines with it for time synchronization.

The Network Time Protocol (NTP) is a networking protocol for clock synchronization between computer systems over packet-switched, variable-latency data networks.

NTP is intended to synchronize all participating computers to within a few milliseconds of Coordinated Universal Time (UTC).


How do I start #NTP on Linux?

In order to add command line options to the ntpd service (/etc/init. d/ntpd), one has to edit /etc/sysconfig/ntpd file and add the desired option to the OPTIONS variable, and restart the service via 'service ntpd restart'.


What port does NTP use?

NTP time servers work within the TCP/IP suite and rely on User Datagram Protocol (UDP) port 123. NTP servers are normally dedicated NTP devices that use a single time reference to which they can synchronize a network. 

This time reference is most often a Coordinated Universal Time (UTC) source.


To Sync NTP client with server via command line:

1. Edit the /etc/ntp.

2. Search for the lines beginning server .

3. Replace the server entries with the IP address or hostname of the NTP server or servers with which you want to synchronize.

4. Save the file.

5. Configure the NTP client service to start at run level 3 when the appliance boots.

Install Wine on Linux Mint 20 - Step by step process to do it ?

This guide will show you steps to install Wine on Linux Mint 20.  Also, you will learn how to remove it once you no longer require this software on your system.

Wine is an open-source, free and easy-to-use program that enables Linux users to run Windows-based applications on Unix-like operating systems. 

Wine is a compatibility layer for installing almost all versions of Windows programs.

The APT is the tool, commonly used to install packages, remotely from the software repository. 

Basically, it's a simple command based tool that you use to install files/software. Complete command is apt-get and it's the easiest way to install files/Software packages.


To uninstall a program in Linux:

To uninstall a program, use the “apt-get” command, which is the general command for installing programs and manipulating installed programs. 

For example, the following command uninstalls gimp and deletes all the configuration files, using the “ -- purge” (there are two dashes before “purge”) command.


How do I delete apt repository?

Whenever you add a repository using "add-apt-repository" command, it will be stored in /etc/apt/sources. list file. 

To delete a software repository from Ubuntu and its derivatives, just open the /etc/apt/sources. 

List file and look for the repository entry and delete it.

Methods to Find Your Private IP Address in CentOS 8 ?

This article will guide you on the different methods to find the private IP address in CentOS 8.


Different ways to display IP addresses in Centos:

1. Using ifconfig command. The ifconfig command is the most commonly used command for displaying and modifying IP addresses on the system.

2. Using ip command.

3. Using the hostname command.

4. using nmcli command.

5. Using ip route show command.


To configure a static IP address on CentOS 7 / RHEL 7:

1. Create a file named /etc/sysconfig/network-scripts/ifcfg-eth0 as follows:

2. DEVICE=eth0.

3. BOOTPROTO=none.

4. ONBOOT=yes.

5. PREFIX=24.

6. IPADDR=192.168.x.xxx.

7. Restart network service: systemctl restart network.


Commands will get you the private IP address of your interfaces:

i. ifconfig -a.

ii. ip addr (ip a)

iii. hostname -I | awk '{print $1}'

iv. (Fedora) Wifi-Settings→ click the setting icon next to the Wifi name that you are connected to → Ipv4 and Ipv6 both can be seen.

v. nmcli -p device show.

Methods to Install Adobe Flash Player on Ubuntu 20.04 LTS ?

This article will guide you on different methods to install Adobe Flash Player on Ubuntu 20.04. 

Once the Adobe Flash Player has been successfully installed on your Ubuntu 20.04 system, it will never render any error while displaying the contents of those websites that are based on the Adobe #Flash platform. 

Moreover, whenever you feel like removing the Adobe Flash Player from your Ubuntu 20.04 system, then you can even remove it using the method described in this guide.


To update #Adobe Flash Player on #Ubuntu:

1. Open "Software & updates" or run software-properties-gtk from terminal.

2. Check all options under "Ubuntu Software" tab.

3. Run sudo apt-get update from terminal followed by sudo apt-get install adobe-flashplugin.

4. Restart Firefox browser if it is already open.

MariaDB on Debian 10 - Step by step process to install it ?

This article will guide you on the different methods to conveniently install and start the MariaDB service on a Debian 10 system. Also, we dealt with how to easily remove MariaDB from your Debian 10 system. 

In MariaDB replication is faster whereas in MySQL replication is slower. 

MariaDB is Open Source whereas MySQL uses some proprietary code in its Enterprise Edition. 

MariaDB doesn't support Data Masking and Dynamic column while MySQL supports it. Comparatively MariaDB is faster than MySQL.

Since MariaDB is a fork of MySQL, the database structure and indexes of MariaDB are the same as #MySQL. 

This allows you to switch from MySQL to MariaDB without having to alter your applications since the data and data structures will not need to change. Data and table definition files are compatible.


To install #MariaDB on #Debian , follow these steps:

1. First update the apt packages index by typing: sudo apt update.

2. Once the packages list is updated, install MariaDB by running the following command: sudo apt install mariadb-server.

3. The MariaDB service will start automatically.

Modify the Date, Time, and Timezone in Ubuntu 20.04 LTS - How to do it ?

This article will guide you on the different methods to modify the date, time, and Timezone of your #Ubuntu 20.04 system. 

However, if you have attempted to change these entities just for the sake of demonstration, then it is highly recommended to activate the #NTP Service again once you are done so that your system can again synchronize itself with NIST atomic clock. 

This can be done by running the “timedatectl set-ntp yes” command.

To change the time zone in Linux systems use the sudo timedatectl set-timezone command followed by the long name of the time zone you want to set.


To change the hostname in #Linux:

1. Type the following command to edit /etc/hostname using nano or vi text editor: sudo nano /etc/hostname. Delete the old name and setup new name.

2. Next Edit the /etc/hosts file: sudo nano /etc/hosts.

3. Reboot the system to changes take effect: sudo reboot.


#NTP server sync date and time in Linux by:

i. On the Linux machine, log in as root.

ii. Run the ntpdate -u <ntpserver> command to update the machine clock. For example, ntpdate -u ntp-time.

iii. Open the /etc/ntp. conf file and add the NTP servers used in your environment.

iv. Run the service ntpd start command to start the NTP service and implement you configuration changes.

Assign Multiple IP Addresses to Single NIC in Ubuntu 20.04 LTS - How to do it ?

This article will guide you on how to assign multiple IP addresses to a single NIC in Ubuntu OS. Now you can allocate multiple IP addresses to a single NIC.

To change your IP address on #Linux, use the "ifconfig" command followed by the name of your network interface and the new IP #address to be changed on your computer. 

To assign the subnet mask, you can either add a "netmask" clause followed by the subnet mask or use the CIDR notation directly.

The ifconfig command can be used from the #command line either to assign an address to a #network interface or to configure or display the current network interface configuration information. 

The ifconfig command must be used at system startup to define the network address of each interface present on a machine.


To determine my IP address in Linux :

1. ifconfig -a.

2. ip addr (ip a).

3. hostname -I | awk '{print $1}'.

4. ip route get 1.2.

5. nmcli -p device show.


To add secondary IP address permanently on Ubuntu system, just edit /etc/network/interfaces file and add the requires IP details. 

Verify the newly added IP address. # ifconfig eth0

Reboot CentOS 8 - Different methods to do it ?

This article will guide you on the different methods to reboot a #CentOS system which includes the keyboard shortcut, command line, and GUI based methods. 

There's nothing different in running sudo reboot in a instance versus on your own server. This action shouldn't cause any problems. 

You can shutdown/start/reboot the instance and your data will persist.

When used with no arguments, the shutdown command will power off the machine. sudo shutdown. 

The shutdown process starts after 1 minute, which is the default time interval.

It is recommended that you do a #reboot of your Server at least once per month. 

The Dedicated Hosting Servers are just computers, you would not leave your computer on for months straight without a single reboot, so the same rules apply for servers.


To reboot your Linux Server via #SSH:

1. Open Command Prompt. If you have a graphical interface, open the terminal by right-clicking the Desktop > left-clicking Open in terminal.

2. Use SSH Connection Issue reboot Command. In a terminal window, type: ssh –t user@server.com 'sudo reboot'.

Install VirtualBox on Ubuntu 20.04 LTS - Step by step process ?

This article will guide you on the different methods to #install #VirtualBox on Ubuntu 20.04 system. Now, you can create your first guest Linux machine or Windows environment on your Ubuntu system. 

#Xen is a popular, open-source virtual machine application that is officially supported by #Ubuntu. 

It provides high performance, but only supports a small number of host and guest operating systems. 

Ubuntu is supported as both a host and guest operating system, and Xen is available in the universe software channel.

If you want to explore more about the working of the Virtualbox then, you can visit the Official documentation of Virtualbox use from this page .

VirtualBox can be installed on #Windows, Linux, macOS, Solaris, and FreeBSD.


To find the #Linux version:

1. Open the terminal application (#bash shell).

2. For remote server login using the ssh: ssh user@server-name.

3. Type any one of the following command to find os name and version in Linux: cat /etc/os-release. lsb_release -a. hostnamectl.

4. Type the following command to find Linux kernel version: uname -r.

NTP Server and Client on Ubuntu - How to Configure it ?

This article will guide you on how to configure the #NTP server on Ubuntu. You will learn how to configure the NTP client on another #Ubuntu machine and synchronize it with the NTP server. By means of this, you can easily synchronize all system clocks in a network.

The Network Time Protocol (NTP) is a networking protocol for clock synchronization between computer systems over packet-switched, variable-latency data networks.

NTP is intended to synchronize all participating computers to within a few milliseconds of Coordinated Universal Time (UTC).


To Configure NTP server:

1. Install NTP Server. First, install NTP package on your server using the appropriate package management tool that is available on your Linux distro.

2. Setup Restrict values in ntp. conf.

3. Allow Only Specific Clients.

4. Add Local Clock as Backup.

5. Setup NTP Log Parameters.

6. Start the NTP Serrver.


To Configure NTP client:

1. To configure your Linux system as an NTP client, you will need to install the ntp daemon (ntpd).

2. The ntpd configuration file is located at /etc/ntp.conf.

3. This file contains the list of NTP servers that will be used for time synchronization.

4. Next, restart the NTP deamon with the sudo service ntp reload command

Remove Duplicates in LibreOffice - Step by step process to do it ?

This article will guide you on how to get rid of duplicates from either the single column or from the multiple columns in LibreOffice. Removing duplicate entries is necessary to clean up the data. With LibreOffice advanced filter tool, you can easily remove these duplicate values from your data.

You can use Libre Office to open and edit existing #MS Office documents like excel word power point etc. 

Libre Office is a free alternate to MS #office and offers same functionality. Its easy to install and use.

The #VLOOKUP function (short for Vertical LOOKUP) is a built-in Calc function that is designed to work with data that is organized into columns. 

For a specified value, the function finds (or looks up) the value in one column of data, and returns the corresponding value from another column.


To find duplicates in #LibreOffice Calc:

1. Go to the worksheet that has the duplicate entries, and select 'Data' > 'Filter' > 'Standard Filter' (it seems to automatically select the data in the sheet that it will filter, you may want to do this manually beforehand).

2. It should then filter the data, and hide any duplicate records.


To insert a date in Libreoffice #Calc:

To enter a current date as a static date, press CTRL+; (semicolon). It will insert today's date as a static value in the corresponding cell. 

Similarly to enter current time as staic value, press CTRL+SHIFT+; .

Methods to Find your Private IP Address in Debian 10 ?

This article will guide you on the different methods through which you can easily figure out the private IP #address of your Debian 10 system.

The network statistics ( netstat ) command is a networking tool used for troubleshooting and configuration, that can also serve as a monitoring tool for connections over the network. Both incoming and outgoing connections, routing tables, port listening, and usage statistics are common uses for this #command.

To find out the #IP address of #Linux system, you need to use the command called ifconfig on #Unix and the ip command or hostname command on Linux. 


To get you the private IP address of your interfaces:

i. ifconfig -a.

ii. ip addr (ip a).

iii. hostname -I | awk '{print $1}'.

iv. ip route get 1.2.

v. (Fedora) Wifi-Settings - click the setting icon next to the Wifi name that you are connected to - Ipv4 and Ipv6 both can be seen.

vi. nmcli -p device show.

Different methods to Reboot Ubuntu 20.04 LTS ?

This article will guide you on the different methods through which you can effectively reboot your #Ubuntu 20.04 system without any difficulty. 

To #reboot immediately, append the -r flag: $ sudo shutdown -r now. 

To power down immediately: $ sudo shutdown -P now. 

You can use the poweroff #command: $ poweroff. 

To reboot after 10 minutes: $ sudo shutdown -r 10.


To reboot Linux using the command line:

1. To reboot the Linux system from a terminal session, sign in or "su"/"sudo" to the "root" account.

2. Then type " sudo reboot " to reboot the box.

3. Wait for some time and the Linux server will reboot itself.

Display System and Hardware Details in CentOS 8 - How to do it ?

This article will guide you on different methods to retrieve information about your #Linux system and the underlying #hardware devices. These procedures will help you check the specifications of your computer machine and you can easily know either the hardware device or computer software is compatible with your working system or not.

The Linux kernel is the main component of a Linux operating system (OS) and is the core interface between a computer's hardware and its processes.


To  find system information in #Centos:

1. To know only system name, you can use uname command without any switch will print system information or uname -s #command will print the kernel name of your system. 

2. To view your network hostname, use '-n' switch with uname command as shown. 

3. To get information about kernel-version, use '-v' switch.

Display System and Hardware Details in Debian 10 - How to do it ?

This article will guide you how to display the system details in your Debian 10 system.

The uname command Displays the operating system name as well as the system node name, operating system release, operating system version, hardware name, and processor type. 

To Check os version in Linux:

1. Open the terminal application (bash shell).

2. For remote server login using the ssh: ssh user@server-name.

3. Type any one of the following command to find os name and version in Linux: cat /etc/os-release. lsb_release -a. hostnamectl.

4. Type the following command to find Linux kernel version: uname -r.


Commands to Check Hardware Information on Linux:

i. lscpu. The lscpu command reports information about the cpu and processing units.

ii. lshw - List Hardware. will give you a very comprehensive list of hardware and settings.

iii. hwinfo - Hardware Information.

iv. lspci - List PCI. will show you most of your hardware in a nice quick way.

v. lsscsi - List scsi devices.

vi. lsusb - List usb buses and device details.

vii. Inxi.

viii. lsblk - List block devices.

Install Linux, Apache, MariaDB, PHP (LAMP) Stack on Debian 10 - Step by step process to do it ?

This guide will help you on how to #install the LAMP stack (Linux, Apache, MariaDB, and PHP ) in your #Debian system. 

LAMP stands for Linux, Apache, MySQL, and PHP. Together, they provide a proven set of software for delivering high-performance web applications.

For a web application to work smoothly, it has to include an operating system, a web server, a database, and a programming language. 

A LAMP Stack is a set of open-source software that can be used to create websites and web applications. 

LAMP is an acronym, and these stacks typically consist of the Linux operating system, the Apache HTTP Server, the MySQL relational database management system, and the PHP programming language.

To Install #LAMP stack on Ubuntu:

1. Update your system. sudo apt-get update.

2. Install Mysql. sudo apt-get install mysql-server mysql-client libmysqlclient-dev.

3. Install #Apache server.

4. Install #PHP (php7.0 latest version of PHP).

5. Install #Phpmyadmin (for #database).

Methods to Find Your Public IP address in Ubuntu 20.04 LTS ?

This guide will help you to Find Your Public IP address in #Ubuntu 20.04 LTS. 

ipconfig stands for Internet Protocol Configuration, while ifconfig stands for Interface Configuration.

The #ifconfig command is supported by Unix-based operating systems.

The ipconfig command displays all the currently connected network interfaces whether they are active or not.

The presence of a #public IP #address on your router or computer will allow you to organize your own server (VPN, FTP, WEB, etc.), remote access to your computer, video surveillance cameras, and access them from anywhere in the global network.


To Find Local / Public IP Address in #Ubuntu 20.04:

1. Open Settings and navigate to Network in left pane.

2. Click on the gear icon under connected wired network.

3. In the pop-up it shows the detailed information including your IP address.


To find my IP address and port number in Linux:

i. All you have to do is type “netstat -a” on Command Prompt and hit the Enter button. 

ii. This will populate a list of your active TCP connections. 

iii. The port numbers will be shown after the IP address and the two are separated by a colon.

Configure Static IP in Debian 10 - Step by step process to do it ?

This article will guide you on the how to set up a static IP configuration in #Debian 10. Using either the command line or #GUI method, you can easily configure the static IP address on your system.

The ifconfig utility is used to change the IP address of a network interface.

To change your #IP address on #Linux, use the “ifconfig” command followed by the name of your network interface and the new IP address to be changed on your computer. 

To assign the subnet #mask, you can either add a “netmask” clause followed by the subnet mask or use the CIDR notation directly.

To Configure static IP address on Ubuntu 16.04 LTS Server:

1. Edit the /network/interfaces file. sudo nano /etc/network/interfaces.

2. Restart the networking service (or reboot) Once you are confident the change has been made, and if you don't want to reboot you can just restart the networking service.

To Display Available Network Interfaces in Linux:

i. ip #command – It is used to show or manipulate routing, devices, policy routing and tunnels.

ii. #netstat command – It is used to display network connections, routing tables, interface statistics, masquerade connections, and multicast memberships.

iii. #ifconfig command – It is used to display or configure a network interface.

Modify Zoom Background on Ubuntu 20.04 - Step by Step process ?

This article will guide you on steps to easily change the background of the Zoom application whenever he wants on #Ubuntu #Linux System. In this way, you can ensure efficient bandwidth utilization.

#Zoom is a very popular video communication tool for chatting, online meetings, screen-sharing, video conferencing etc. 

It is supported by most of the popular operating system like #Windows, Linux, Mac, and Android.

Zoom offers a few default image options to choose from, but it also allows you to upload your own image.

To make my background zoom better:

1. Click Settings. 

2. Click Virtual Background. 

Note: If you do not have the Virtual Background tab and you have enabled it on the web portal, sign out of the Zoom Desktop Client and sign in again. 

3. Click on an image to select the desired virtual background or add your own image by clicking +Add Image.

Install MongoDB ( NoSQL ) on Linux (Ubuntu 20.04) - Step by step process ?

This article will guide you on how to add MongoDB’s official #repository and install the latest stable release of MongoDB #NoSQL in the #Ubuntu 20.04 LTS system. 

Also, you will learn how to completely uninstall from the system in case you no longer need it.

MongoDB stores data in db folder within data folder. But, since this data folder is not created automatically, you have to create it manually. 

Remember that data directory should be created in the root (/).

To get stats about #MongoDB server, type the command db. stats() in MongoDB client. 

This will show the database name, number of collection and documents in the database.

In MongoDB, data is stored as documents. 

These documents are stored in MongoDB in JSON (JavaScript Object Notation) format. 

#JSON documents support embedded fields, so related data and lists of data can be stored with the document instead of an external table.

Methods to Log Out of Debian 10 ?

This article will guide you on how you can log out from your Debian 10 system. Here, you will learn the different methods of logging out of a #Debian system. 

exit command in #linux is used to exit the shell where it is currently running. 

It takes one more parameter as [N] and exits the shell with a return of status N. 

If n is not provided, then it simply returns the status of last #command that is executed. Syntax: exit [n].

pkill is a command-line utility that sends signals to the processes of a running program based on given criteria. 

The processes can be specified by their full or partial names, a user running the process, or other attributes.

Methods to Log Out of Linux Mint 20 ?

This article will guide you on methods to logout from the Linux #Mint. Based on your convenience, you can use either the keyboard shortcut or the system menu to logout from your session. When you use a terminal or if you log in to an #Ubuntu system via #SSH, you open a shell session. If you want to logout from your session, you simply exit the #shell. This is why the exit command is equivalent to log out command in Linux.

To switch users in #Linux:

The su command lets you switch the current user to any other user. 

If you need to run a command as a different (non-root) user, use the –l [username] option to specify the user account. 

Additionally, su can also be used to change to a different shell interpreter on a go.

Methods to Log out of Ubuntu 20.04 LTS ?

This article will guide you on different methods to log out of your #Ubuntu 20.04 system very conveniently. By logging out of a current user session, we essentially attempt to stop all the running #applications. 

It means that when we will log into the same user account again, we will have to start everything from scratch.

Steps to Log Out from Ubuntu #Linux:

1. To log out from Ubuntu desktop #session, go to the top right corner and click to bring the system tray. 

2. You should see Power Off / Log Out option. 

3. Click on it and it will show the Log Out option. 

4. When you click on the Log Out button, it will open a dialogue box and ask for your conformation.

You can Use #logout to log out of the #terminal. Or alternatively we can use ctrl + d to log out of the terminal session.

Methods to log out of CentOS 8 ?

This article will guide you on different methods to log out of the #CentOS 8 #Linux system. Therefore, If you want to close the current user session then, Logging out of the system is the best choice. 

The main difference between these tools is that kill terminates processes based on Process ID number (PID), while the killall and pkill commands terminate running processes based on their names and other attributes.

To exit CentOS 7:

i. Simply use 'Ctrl-C' to kill terminal commands in linux. 

ii. Ctrl-D should be used to terminate nl correctly. 

iii. Ctrl-C is just a general way to kill #applications.

NFS Client and Server - Step by step process to configure on Debian 10 Linux System

This article will guide you on how you can setup NFS server and client in Debian 10 system. Also, you will learn steps to install the NFS server and client, configure NFS shared directories, and mount/unmount the NFS shares on the client system.

Configuring a system to share files and directories using NFS is straightforward. 

NFS uses port 2049. NFSv3 and NFSv2 use the portmapper service on TCP or UDP port 111.

Every filesystem being exported to remote users via NFS, as well as the access rights relating to those filesystems, is located in the /etc/exports file.

To check #NFS mount #Linux:

1. Use showmount to show NFS shares.

2. Use exportfs to show NFS shares.

3. Use master export file /var/lib/nfs/etab to show NFS shares.

4. Use mount to list NFS mount points.

5. Use nfsstat to list NFS mount points.

6. Use /proc/mounts to list NFS mount points.


How to uninstall programs from Linux Mint ?

This article will guide you on methods to remove or #uninstall a program in #Linux #Mint 20. 

To uninstall a program, use the "apt-get" command, which is the general command for installing programs and manipulating installed programs.

If you want to remove a package, use the apt in the format; sudo apt remove [package name]. If you want to remove a package without confirming add –y between apt and remove words.

To uninstall an RPM package:

1. Execute the following command to discover the name of the installed package: rpm -qa | grep Micro_Focus. This returns PackageName , the #RPM name of your Micro Focus product which is used to identify the install package.

2. Execute the following command to uninstall the product: rpm -e [ PackageName ]


To clean up broken #packages in #Ubuntu:

i. Find your package in /var/lib/dpkg/info , for example using: ls -l /var/lib/dpkg/info | grep <package>

ii. Move the package folder to another location.

iii. Run the following command: sudo dpkg --remove --force-remove-reinstreq <package>

Listing Users in Linux - How to do it ?

This article will guide you on the different methods to list down all the Linux system users. To know whether a particular user is having sudo access or not, we can use -l and -U options together. For example, If the user has sudo access, it will print the level of #sudo access for that particular user. 

If the user don't have sudo access, it will print that user is not allowed to run sudo on localhost.

To change users in #Linux:

The su command lets you switch the current user to any other user. 

If you need to run a command as a different (non-root) user, use the –l [username] option to specify the user account. 

Additionally, su can also be used to change to a different shell interpreter on the fly.

Ways to Shutdown CentOS 8

This article will guide you on different ways to shut down CentOS system. Using either of the above-discussed command line or GUI way, you can easily shutdown your #CentOS system.

To shut down the system from a terminal session, sign in or "su" to the "root" account. Then type ``/sbin/shutdown -r now''. 

It may take several moments for all processes to be terminated, and then Linux will shut down.

In #Unix and #Linux, the shutdown command can be used to turn off or reboot a computer. Only the superuser can shut the system down. 

One commonly issued form of this command is shutdown -h now , which will shut down a system immediately. 

Another one is shutdown -r now to reboot.

Ways to Find Your IP address in Ubuntu 20.04 LTS

This article will guide you on how to check your private IP address in #Ubuntu 20.04 LTS system. 

ifconfig command is used to display or configure a network interface.

To use command prompt (CMD) to find my #IP #address:

1. Open the command prompt: if you have a Start menu in your Windows system, open it and type cmd into the search bar.

2. Type ipconfig into the command prompt (or the Run box).

3. Find your IP address within the text that pops up.

You can also use the following commands will get you the private IP address of your interfaces:

i. ifconfig -a.

ii. ip addr (ip a)

iii. hostname -I | awk '{print $1}'

iv. nmcli -p device show.

Step by step process to install and use Steam on Ubuntu 20.04 LTS ?

This article will guide you on how to #install and get started with Steam on Ubuntu 20.04 LTS. Steam on Linux made it easier for various hardcore gamers to switch to #Linux from Windows or #Mac for professional reasons.

Ubuntu is the best OS for developers because of the various libraries, examples, and tutorials. These features of ubuntu help considerably with AI, ML, and DL, unlike any other OS. 

Furthermore, Ubuntu also provides reasonable support for the latest versions of free open source software and platforms.

To Install #Steam from Ubuntu package #repository:

1. Confirm that the multiverse Ubuntu repository is enabled: $ sudo add-apt-repository multiverse $ sudo apt update.

2. Install Steam package: $ sudo apt install steam.

Use your desktop menu to start Steam or alternatively execute the following command: $ steam.


To play steam on #Linux:

i. To get started, click the Steam menu at the top-left of the main Steam window, and select 'Settings' from the dropdown. 

ii. Then click 'Steam Play' on the left side, make sure the the box that says 'Enable Steam Play for supported titles' is checked, and check the box for 'Enable Steam Play for all other titles'.

Shutter Screenshot Tool on Ubuntu 20.04 LTS - Step by step process to install and use it ?

This article will guide you on methods to install and use the Shutter screenshot tool on Ubuntu 20.04. Once installed on your #Ubuntu Server , you can conveniently use it to take the screenshots as per your requirements and can even edit them if needed.

#Shutter is a screenshot tool in Ubuntu #Linux. Using Shutter we can take a screenshot of a specific area, window and whole screen.

Shutter allows you to capture nearly anything on your screen without loosing control over your screenshots (tabbed interface). 

Features of Shutter:

1. Capture a Specific Area

This allows you to select an arbitrary region of your screen and capture only those parts you really need. The screen can be zoomed and the selection can be resized or moved.

2. Capture your Desktop

Shutter does not only capture all the contents of your desktop (or workspace) – it also supports Multi-monitor settings, e.g. capture the active monitor

3. Capture a Window

Simply use your mouse to select the window you want to capture. Shutter will highlight the currently select window in an attractive and useful way. It is even possible to simply select a window from a list and capture it right a way.

4. Capture a Menu or Tooltip

Capturing menus or tooltips is very easy with Shutter. You select one of the options and a (user-defined) countdown starts. During this time you can open the desired menu or let a specific tooltip come up. Shutter will recognize and capture it.

5. Capture a Website

Shutter uses gnome-web-photo to capture a website without opening a browser window

Different methods to check memory usage in Debian 10 ?

This article will guide you on methods to check the #memory usage in #Debian 10. You can easily visualize from the way these methods have been explained that they are so simple and easy to carry out. 

Therefore, you can find out the available and used memory in Debian 10 at any time you want without any hassle.

Swap space in Linux is used when the amount of physical memory (#RAM) is full. If the system needs more memory resources and the RAM is full, inactive pages in memory are moved to the swap space.

To kill a process in Linux:

1. View Running #Linux #Processes.

2. Locate the Process to #Kill. Locate a Process with ps Command. Finding the PID with pgrep or pidof.

3. Use Kill Command Options to Terminate a Process. killall Command. pkill Command.

4. Key Takeaways on Terminating a Linux Process.

Different Methods to Shutdown Linux Mint 20 ?

This article will guide you on the different methods of shutting down a #Linux Mint 20 system. Whenever you are done with your work on your Linux #Mint 20 system, you can easily pick any method out of these four to turn off your system till you wish to use it again.

sudo chmod u+s /sbin/shutdown

You will be prompted for your root password. After that, you're done and can type "exit" to exit out of the Terminal.

To schedule a #shutdown, add the [time] argument and specify when you want it to take place. There are two ways to shut down the system at a specific time – using the absolute or relative time format.

To  restart Linux Mint:

1. You can go back to the login screen and close your entire session (losing all open applications) by pressing Ctrl+Alt+Backspace. 

2. If your system doesn't respond to that you can cleanly reboot your system by holding down Alt + SysRq and slowly typing the letters "r e i s u b" in that order.

Some Useful VLC Media Player Shortcut Keys

This article will guide you on #shortcuts you can use in VLC media player which can control this application very conveniently. Doing this will not only increase your productivity but will also save your time in locating and using the GUI based controls.

To Edit #VLC Media Player Shortcuts (Hotkeys):

1. In the Menu Bar click on Tools and then “Preferences” [CTRL + P is the shortcut].

2. On the left of the preferences option go to “Hotkeys”.

3. To edit a shortcut double click on one of those Action or Hotkey.

4. A “Hotkey Change” option is displayed.

5. If the shortcut is already used up then a warning is displayed.

Different useful LibreOffice writer shortcut keys ?

This article will guide you on how to use shortcut keys when dealing with #LibreOffice Writer documents.

These #shortcut key combinations will ease your life a lot as they will save your time that is spent in performing the most frequently used operations.

If the active cell is empty Ctrl+A selects the whole table; otherwise it selects the contents of the active cell. Depressing Ctrl+A a second time selects the entire table. If the active cell is empty Ctrl+Home moves the cursor to the beginning of the table.

To make a table in LibreOffice writer:

1. Place the cursor in your document where you want to insert the table.

2. Choose Table - Insert - Table.

3. In the Size area, enter the number of rows and columns.

4. Select the options that you want, click OK.

Different methods to uninstall programs from CentOS 8 ?

This article will guide you on methods to uninstall a #package using #Yum. You need to just type the package name with root privileges. Moreover, we have also seen how to remove a single package, multiple, and group by using the Yum package manager.

apt remove just removes the binaries of a package. 

It leaves residue configuration files. apt purge removes everything related to a package including the configuration files.

To uninstall a program in #Linux Mint terminal:

1. Uninstall software in Linux mint from the main menu.

2. Confirm that you want to #remove the package.

3. Open the Software Manager.

4. Search for a program to remove using the software manager.

5. Remove software in Linux #Mint using the software manager.

6. Open Synaptic package manager.