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Related to commands


Install PowerShell on Linux Mint 20.3 Una system - Step by step guide ?

This article covers how to easily Install PowerShell on Linux Mint system. In fact, PowerShell is commonly used for automating the management of systems. It is also used to build, test, and deploy solutions, often in CI/CD environments.

Use the Netcat Command to Read and Write Data Across the Network on Ubuntu 20.04

This article covers information about the usage of Netcat with TCP and UDP protocol and some other uses like scanning ports, sending files, and creating a web server. In fact, Netcat is a basic Linux utility that uses the TCP/UDP protocols for reading and writing data across network connections. It's intended to be a dependable backend tool that may be operated directly or simply by other applications and programs. 

'kubectl get' Command - Explained with Examples

This article covers kubectl Commands with Examples. In fact, Kubectl is a set of commands for controlling Kubernetes clusters. Every Kubernetes command has an API endpoint, and kubectl’s primary purpose is to carry out HTTP requests to the API.

While it is possible to issue HTTP requests yourself (e.g., using curl), kubectl is designed to make this process more comfortable and straightforward.


How to delete Resources using kubectl command ?

To remove resources from a file or stdin, use the kubectl delete command.

1. Remove a pod using the name and type listed in pod.yaml:

$ kubectl delete -f pod.yaml

2. Remove all pods and services with a specific label:

$ kubectl delete pods,services -l [label-key]=[label-value]

3. Remove all pods (including uninitialized pods):

$ kubectl delete pods --all

Install Smartctl on Ubuntu 20.04 - Step by step guide ?

This article covers the complete steps to install smartctl on Ubuntu 20.04. In fact, the smartmontools package contains two utility programs (smartctl and smartd) to control and monitor storage systems using the Self-Monitoring, Analysis and Reporting Technology System (S.M.A.R.T.) built into most modern ATA and SCSI hard disks. It is derived from the smartsuite package, and includes support for ATA/ATAPI-5 disks. It should run on any modern Linux system.


How to Install smartmontools Using apt-get on Ubuntu / Debian system ?

1. Update apt database with apt-get using the following command:

$ sudo apt-get update

2. After updating apt database, We can install smartmontools using apt-get by running the following command:

$ sudo apt-get -y install smartmontools

Linux wget Command - Explained with Examples

This article covers the wget command which downloads files served with HTTP, HTTPS, or FTP over a network. In fact, Wget is a free GNU command-line utility tool used to download files from the internet. It retrieves files using HTTP, HTTPS, and FTP protocols.



Wget command options includes:

  • -V, --version: Display the version of wget, and exit.
  • -h, --help: Print a help message describing all the wget's command-line options, and exit.
  • -b, --background: Go to background immediately after startup. If no output file is specified via the -o, output is redirected to wget-log.
  • -e command,
  • --execute command: Execute command as if it were a part of the file .wgetrc. A command thus invoked is executed after the commands in .wgetrc, thus taking precedence over them.


How to Check if wget is Installed?

To check, open the terminal window and type in:

$ wget

If the output displays wget command not found you need to download and install the tool manually. Below you will find the installation instructions for Ubuntu/Debian, CentOS, and Windows.

To install wget on Ubuntu or Debian releases, use the command:

$ sudo apt-get install wget

To install wget on CentOS or Fedora, type the following command:

$ sudo yum install wget


How to Install wget on Windows ?

  • Download wget for Windows and install the package.
  • Add the wget bin path to environment variables (optional). Configuring this removes the need for full paths, and makes it a lot easier to run wget from the command prompt:
  • Open the Start menu and search for "environment".
  • Select Edit the system environment variables.
  • Select the Advanced tab and click the Environment Variables button.
  • Select the Path variable under System Variables.
  • Click Edit.
  • In the Variable value field add the path to the wget bin directory preceded by a semicolon (;). If installed in the default path, add C:Program Files (x86)GnuWin32bin.
  • Open the command prompt (cmd.exe) and start running wget commands.

Methods to List All Available Commands and Aliases in Linux

This article covers how to list all the available commands and aliases that we can run on Linux. In fact, The compgen is bash built-in command and it will show all available commands, aliases, and functions for you. This command works under Linux, macOS, *BSD and Unix-like system when Bash shell is installed. 

Monitor User Activity With acct Tool on Ubuntu 20.04

This article covers how to monitor user activity with the acct tool on Ubuntu 20.04. In fact, Acct can monitor the user activity & getting the information about the user performance. It provides the information about last commands executed by users, user logins / logouts details in hours by day-wise, system activity information,& individuals user information.


How to install acct on ubuntu ?

1. Update the System:

$ apt-get update

2. Install the psacct or acct on system:

$ apt-get install acct

3. Check the acct version:

$ ac --version

Install Tmux on Linux Mint 20 - Step by step guide ?

This article covers the process of installing Tmux on a Linux Mint 20 system. In fact, Tmux is a popular multiplexer which makes it easy for you to run different applications in separate sessions and switch between them effortlessly.

Tmux is a Linux application that allows multitasking in a terminal window. It stands for Terminal Multiplexing, and is based around sessions. Users can start a process, switch to a new one, detach from a running process, and reattach to a running process.


How to Install Tmux in Linux ?

1. On Debian-based distributions:

$ sudo install tmux

2. On CentOS/REHL:

$ yum install tmux

3. To install tmux on Arch Linux:

$ pacman -S tmux

Once the installation is finished, launch a terminal and type in tmux to start a fresh tmux session:

$ tmux

Install ADB and Fastboot on Ubuntu 20.04 LTS - Step by step guide ?

This article covers the process to install the ADB and Fastboot on Ubuntu 20.04 LTS Focal Fossa system. In fact, ADB or Android Debug Bridge is a command-line utility that lets us control an android device from the computer itself. Its part of Google Android SDK & can be used to run shell commands or to copy the files to & from the device & also to install or remove the applications from the device.

Fastboot is basically a diagnostics mode that is used to modify the Android file system from the computer when the android device is in bootloader mode. It’s an alternative to recovery mode & is normally used to perform updates or to perform installations.



How to install ADB & Fastboot on Ubuntu systems ?

1. To install both the ADB & Fastboot, execute the following command from the terminal:

$ sudo apt-get install android-tools-adb android-tools-fastboot

2. Once the installation has been finished you can check the ADB version by running the following command:

$ adb version

Reset Root Password on Rocky Linux - How to do it ?

This article covers the process of Resetting the root password on Rocky Linux. In fact, If you are locked out of your AlmaLinux instance and have lost access to the root account, you need to boot into single-user mode and reset the root password.

Procinfo Command in Linux Explained with examples

This article covers how to install procinfo software package on your Ubuntu Linux system. In fact, the file /proc/cpuinfo displays what type of processor your system is running including the number of CPUs present. 


How to install the procinfo command ?

You can install it using following command:

$ sudo apt install procinfo		#Debian/Ubuntu
$ sudo yum install procinfo #CentOS/RHEL
$ sudo dnf install procinfo #Fedora 22+


The simplest example is to run procinfo without any arguments:

$ procinfo

Monitor Linux performance using sysstat tool

This article covers how to install Linux Sysstat Utilities For Monitoring System Performance. In fact, Sysstat is a powerful monitoring tool for Linux environments. 

Basically, Sysstat is actually a collection of utilities designed to collect information about the performance of a Linux installation and record them over time.


Main features of Sysstat:

  • Display average statistics values at the end of the reports.
  • On-the-fly detection of new devices (disks, network interfaces, etc.) that are created or registered dynamically.
  • Support for UP and SMP machines, including machines with hyperthreaded or multi-core processors.
  • Support for hotplug CPUs (it detects automagically processors that are disabled or enabled on the fly) and tickless CPUs.
  • Works on many different architectures, whether 32- or 64-bit.
  • Needs very little CPU time to run (written in C).
  • System statistics collected by sar/sadc can be saved in a file for future inspection. You can configure the length of data history to keep. There is no limit for this history length but the available space on your storage device.
  • System statistics collected by sar/sadc can be exported in various different formats (CSV, XML, JSON, SVG, etc.). DTD and XML Schema documents are included in sysstat package. JSON output format is also available for mpstat and iostat commands.
  • iostat can display statistics for devices managed by drivers in userspace like spdk.
  • Smart color output for easier statistics reading.

Different methods of installing Sysstat on any Linux distribution ?

1. Install from RHEL/Fedora/CentOS

Execute:

$ sudo yum install sysstat

CentOS and Fedora systems call the collector process using a cron job in /etc/cron.d and it's enabled by default. On recent versions, systemd is used instead of cron. You may need to enable and start the sysstat service:

$ sudo systemctl enable sysstat
$ sudo systemctl start sysstat


2. Install from Ubuntu

Execute:

$ sudo apt-get install sysstat

Then enable data collecting:

$ sudo vi /etc/default/sysstat

change ENABLED="false" to ENABLED="true"

save the file

Last, restart the sysstat service:

$ sudo service sysstat restart


3. Install Sysstat from sources

Clone sysstat public repository with:

$ git clone git://github.com/sysstat/sysstat

Then configure sysstat for your system:

$ cd sysstat
$ ./configure

You can set several variables and parameters on the command line. For example you can enter the following option to activate data collecting (either using cron or systemd):

$ ./configure --enable-install-cron

Enter ./configure --help to display all possible options.

Finally, Compile and install:

$ make
$ sudo make install

Create a virtual machine in KVM on the command line

This article covers how to create and manage guest virtual machines on KVM from the command-line. In fact, KVM (Kernel based Virtual Machine) is an opensource virtualization technology built for Linux machines. It comprises a kernel module – kvm.ko which provides the core virtualization platform and a processor-specific module ( kvm-intel.ko for Intel processors or kvm-amd.ko for AMD processors ).


How to Install KVM, Qemu, virt-manager & libvirtd daemon ?

To install KVM and associated packages, run the below command:

$ sudo apt install -y qemu qemu-kvm libvirt-daemon libvirt-clients bridge-utils virt-manager

The command installs the following packages:

  • qemu-kvm –  This is the main KVM package that provides virtualization support.
  • libvirt – Includes the libvirtd daemon which supports creation and management of virtual machines.
  • libvirt-client – This package provides the virsh utility used for interacting with virtual machines.
  • virt-install – A utility that helps you to create virtual machines and install OS on those virtual machines from command line.
  • virt-viewer – A utility that displays the graphical view for the virtual machine.

Once installed, we need to confirm if the required kvm modules are loaded. Therefore, run the command:

$ lsmod | grep kvm

Additionally, confirm that the libvirtd daemon is running as follows:

$ sudo systemctl status libvirtd.service

Install PowerShell on Ubuntu 20.04 LTS - A step by step guide ?

This article covers the process of installing the latest stable version of Microsoft PowerShell on the Ubuntu 20.04 LTS  (Focal Fossa) system. In fact, PowerShell is a task-based configuration tool used to automate system administrator tasks. 

Install and Configure CSF(Config Server Firewall) on Ubuntu 20.04 LTS

This article covers the process of installing Config Server Firewall on Ubuntu 20.04. In fact, Config Server Firewall (CSF) is a popular security tool for Linux comes with multiple features such as stateful packet inspection firewall (SPI), intrusion detection, a login failure daemon, DDOS protection, and control panel integration.

For additional help or useful information, we recommend you check the official CSF website .

Alias Command in Linux - With Examples

This article covers how to create aliases and use the alias command in Linux. In fact, the alias command instructs the shell to replace one string with another when executing commands. Aliases are used to customize the shell session interface. Using alias, frequently-used commands can be invoked using a different, preferred term; and complex or commonly-used options can be used as the defaults for a given command.

Install Yay AUR Helper in ArchLinux

This article covers how Yay AUR helper works and to easily install and manage software applications. In fact, Yay is an Aur helper which is Written in the Golang Go language and was developed with minimal dependencies and minimal user input. It performs just as well as Pacman and has an interactive search/install functionality. Also, It allows you to TAB complete, download PKGBUILDs from AUR or  ABS, and locates matching package providers during a search operation. 

Install HexChat on Debian - The easiest method ?

This article covers how to install and remove HexChat 10 buster edition. In fact, HexChat is a nice chatting utility to connect with IRC servers.

Installing hexchat package on Ubuntu is as easy as running the following commands on terminal:

$ sudo apt-get update
$ sudo apt-get install hexchat


How to Install HexChat in Linux ?

Run the below command as per your Linux distribution:

$ sudo apt install hexchat [On Debian/Ubuntu & Mint]
$ sudo yum install hexchat [On CentOS/RHEL 7]
$ sudo dnf install hexchat [On CentOS/RHEL 8 & Fedora]
$ sudo yay -S hexchat [On Arch Linux]
$ sudo zypper install hexchat  [On OpenSUSE Linux]
$ sudo pkg install hexchat [On FreeBSD]

Install Alpine email client on Debian 10 - Follow these steps ?

This article covers how to install, run, and remove Alpine on Debian 10, which is an amazing email client full of features to run in the terminal forever. In fact, Alpine is a CLI email client for BSD and GNU/Linux. 


How to install Alpine on Linux ?

For EL7:

$ sudo yum -y install alpine

For Fedora:

$ sudo dnf -y install apline

For Debian & Ubuntu & derivatives:

$ sudo apt -y install alpine

Linux Server Hardening – Best practices to apply ?

This article covers some best practices to harden Linux systems. In fact, Securing your Linux server(s) is a difficult and time consuming task for System Administrators but its necessary to harden the server’s security to keep it safe from Attackers and Black Hat Hackers. You can secure your server by configuring the system properly and installing as minimum software as possible.

Linux pwd Command - An overview with examples

This article covers how to use the pwd command in Linux. In fact, pwd Linux command is mainly used for printing the name of the current working directory. Examples of printing the current working directory, avoiding symlinks and how to get the current working directory in shell scripts.

Install CUPS Print Server on Linux Mint 20 - Best Method ?

This article covers steps to install the CUPS print server on a Linux Mint 20 system. In fact, Linux uses the Common UNIX Printing System, also known as CUPS. CUPS uses the Internet Printing Protocol (IPP) to allow local printing and print sharing. The /etc/cups/ directory stores all the configuration files for printing. However, these files can be easily managed with the Printer Configuration Tool in Linux. Once it is installed on your system, you can use it very effectively for managing multiple printers and computers that wish to use those printers.

Best Open Sources Shells in Linux

This article covers the most popular shells among Linux users. In fact, Shell is an environment in which we can run our commands, programs, and shell scripts. There are different flavors of a shell, just as there are different flavors of operating systems. Each flavor of shell has its own set of recognized commands and functions. As Linux is flexible we can switch between shells easily without any additional configuration.


What is a Shell Prompt in Linux ?

The prompt, $, which is called the command prompt, is issued by the shell. While the prompt is displayed, you can type a command.

Shell reads your input after you press Enter. It determines the command you want executed by looking at the first word of your input. A word is an unbroken set of characters. Spaces and tabs separate words.

Following is a simple example of the date command, which displays the current date and time:

$date
Thu Jun 25 08:30:19 MST 2021


Functions of Linux kernel:

  • Controls all computer operations.
  • Coordinates all executing utilities.
  • Ensures that executing utilities do not interfere with each other or consume all system resources.
  • Schedules and manages all system processes.

Manage Linux File System on Ubuntu Linux Server

This article covers how to keep check and balance on your file system. Ext4 is the default file system on most Linux distributions for a reason. It's an improved version of the older Ext3 file system. It's not the most cutting-edge file system, but that's good: It means Ext4 is rock-solid and stable.

If you're setting up partitions on your main Linux boot drive, you'll also want to create a swap partition of at least a few GBs in size when setting up those partitions. This partition is used for "swap space". It's similar to the paging file on Windows. Linux swaps out memory to the swap space when its RAM is full. This partition must be formatted as "swap" instead of with a particular file system.

Configure and Use Git on Debian - Best Procedure ?

This article covers steps to install and configure Git on a Debian 10 server. As one of the most popular version control systems currently available, Git is a common choice among open-source and other collaborative software projects. Many project's files are maintained in a Git repository, and sites like GitHub, GitLab, and Bitbucket help to facilitate software development project sharing and collaboration.


How to install Git on Debian / Ubuntu Linux System ?

1. Use the apt package management tools to update your local package index and then download and install Git:

$ sudo apt update
$ sudo apt install git

2. You can confirm that you have installed Git correctly by running the following command:

$ git --version

Check Internet speed from command line in Linux Mint

This article covers different ways to measure and monitor your internet bandwidth in Linux Mint System. Speedtest CLI is a command-line tool that is tailored for system administrators and developers, and command-line enthusiasts. It provides the capability of checking the internet speeds straight from your Linux terminal.


Speedtest CLI allows you to do the following:

  • Check the bandwidth performance including metrics such as download, upload, and packet loss.
  • Check the connection from your PC or even a remote server and IoT devices such as Raspberry Pi.
  • Configure scripts to collect speed test results over a period of time.
  • Save results in CSV or JSON.


How to Check version of Speedtest-cli in Linux Mint ?

To check the version of the Speedtest-cli tool, run the command:

$ speedtest-cli --version

Hwinfo Command in Linux - An Overview ?

This article covers how to use the hwinfo command in Linux. hwinfo command reports information about CPU, RAM, keyboard, mouse, graphics card, sound, storage, network interface, disk, partition, bios, and bridge, etc,.


The hwinfo utility displays the following information:

  • CPU : manufacturer, model, frequency
  • Motherboard : manufacturer, model, BIOS version, on-board controller
  • RAM : RAM size, RAM type (FP, EDO, SDRAM, DDRAM)
  • Hard disk controller : SCSI, IDE, on-board/card, model, BIOS version, chipset
  • Hard disks : type, manufacturer, model, size, bus system (SCSI, IDE), partitioning
  • CD-ROM drives : type, manufacturer, model, speed, internal/external, parallel port?
  • Other media : CD writer, streamer (model, manufacturer, SCSI/EIDE/floppy streamer, capacity), ZIP drives, Jaz drives, MO drives, flopticals
  • Graphics card : model, manufacturer, chipset, memory (DRAM, VRAM), memory size
  • Other peripherals : printer, parallel ports, serial ports, modem, ISDN card

Df Command in Linux - How is works ?

This article covers how to use the df command in Linux. You can use the df command when you need to know how much space is available on a particular file system or to see an overview of mounted files systems.

If you want to display all the file system, use -a option:

df -a


Options for df command includes:

  • -a, –all : includes pseudo, duplicate and inaccessible file systems.
  • -B, –block-size=SIZE : scales sizes by SIZE before printing them.
  • -h, –human-readable : print sizes in power of 1024.
  • -H, –si: print sizes in power of 1000.
  • -i, –inodes : list inode information instead of block usage.
  • -l, –local : limit listing to local file systems.
  • -P, –portability : use POSIX output format.
  • –sync : invoke sync before getting usage info.
  • –total : elide all entries insignificant to available space, and produce grand total.
  • -t, –type=TYPE : limit listing to file systems of type TYPE.
  • -T, –print-type : print file system type.

Install and Use Logwatch on Linux Mint 20 - Step by Step Process ?

This article covers how to install the Logwatch utility on your Linux server. With Logwatch, you will be able to keep an eye on your server logs and hence, you can quickly figure out any possible issues.

You can easily customize Logwatch to your preference by modifying the parameters in the /etc/logwatch/conf path. It also provides something extra in the way of pre-written PERL scripts for making log parsing easier.

All the default settings are defined in the /usr/share/logwatch/default.conf/logwatch.conf file. The recommended practice is to leave this file intact and instead create your own configuration file at the /etc/logwatch/conf/ path by copying the original config file and then define your custom settings.


Logwatch comes with a tiered approach and there are 3 main locations where configuration details are defined:

  • /usr/share/logwatch/default.conf/*
  • /etc/logwatch/conf/dist.conf/*
  • /etc/logwatch/conf/*


To install Logwatch on your server.

On Ubuntu:

$ sudo apt-get install logwatch

On Debian:

$ apt-get install logwatch

Use pkill Command in Linux System - An overview ?

This article covers how to use the pkill command in Linux. pkill is basicity a wrapper around the pgrep program that only prints a list of matching processes.

The syntax for the pkill command is as follows:

$ pkill [OPTIONS] <PATTERN>

The matching <PATTERN> is specified using extended regular expressions.

For more information about pkill command, visit the pkill man page or type man pkill in your terminal.


Other Linux commands:

  • ps — Report the status of a process or processes.
  • killall — Kill processes by name.
  • kill — Send a signal to a process, affecting its behavior or killing it.

Install Emacs Editor on CentOS 8 - Best Method ?

This article covers different methods to install the emacs editor on CentOS 8 system. Emacs is one of the oldest and most versatile text editors available for Linux and UNIX-based systems. It's been around for a long time (more than twenty years for GNU emacs) and is well known for its powerful and rich editing features. Emacs is also more than just a text editor; it can be customized and extended with different "modes", enabling it to be used like an Integrated Development Environment (IDE) for programming languages like Java, C or Python.


To Install Emacs via EPEL repository, Run the following command:

$ sudo dnf update
$ sudo dnf install epel-release
$ sudo dnf install emacs

Install Putty on CentOS 8 - Best Method ?

This article covers how to Install putty on CentOS 8. With putty, you can easily connect your Linux system to a remote system. Putty is a free and open source ssh & telnet client. Putty is available for Windows, Linux, Unix and macOS. Using putty, we can access the remote servers and switches over ssh protocol. It can also be used to take serial console of remote systems.


How to perform Putty Installation on CentOS / RHEL / Fedora ?

Putty package is available in the default CentOS and RHEL repositories. So, to install putty run:

$ sudo yum install putty -y

Or

$ sudo dnfs install putty -y

10 Most Useful Ubuntu Linux Commands

This article covers some useful Linux commands to help you get started with working efficiently with Linux system. When operating a Linux OS, you need to use a shell — an interface that gives you access to the operating system’s services. Most Linux distributions use a graphic user interface (GUI) as their shell, mainly to provide ease of use for their users.

That being said, it's recommended to use a command-line interface (CLI) because it’s more powerful and effective. Tasks that require a multi-step process through GUI can be done in a matter of seconds by typing commands into the CLI.


How to use the cd command in Linux ?

To navigate through the Linux files and directories, use the cd command. It requires either the full path or the name of the directory, depending on the current working directory that you're in.

There are some shortcuts to help you navigate quickly:

  • cd .. (with two dots) to move one directory up.
  • cd to go straight to the home folder.
  • cd- (with a hyphen) to move to your previous directory.


How does the ls command works ?

The ls command is used to view the contents of a directory. By default, this command will display the contents of your current working directory.

There are variations you can use with the ls command:

  • ls -R will list all the files in the sub-directories as well.
  • ls -a will show the hidden files.
  • ls -al will list the files and directories with detailed information like the permissions, size, owner, etc.

Set Up UFW Firewall on Ubuntu 18.04 - Best Method ?

This article covers how to set up UFW on Ubuntu 18.04 system. It advised to deny all the incoming connections except necessary ports. Uncomplicated Firewall or UFW is an interface to iptables that is designed to simplify the process of configuring a firewall. While iptables is a firm and flexible tool, it can be sometimes tricky for beginners to learn how to use it to properly configure a firewall. If a user is looking to get started securing his or her network, UFW may be the appropriate solution.


UFW is installed on Ubuntu by default. If it has been uninstalled for some reason, we can install it with the following command:

$ sudo apt install ufw

By default, UFW denies all incoming connections and allows all outgoing connections. It means that a client trying to reach our server would not be able to connect. When an application from our server tries to connect any other server outside, it will be allowed. The following commands serve the purpose:

$ sudo ufw default deny incoming
$ sudo ufw default allow outgoing

Most Useful Nginx Commands in Linux System

This article covers most used Nginx commands. You can learn more about Nginx command line at Nginx documentation.

Nginx is one of the most popular web servers in the world. So whether you're currently using it or not, chances are, if you're a web developer chances are you'll likely come in contact with it at some point. 

Also, Nginx is well known for its simple configuration, and low resource consumption due to its high performance, it is being used to power several high-traffic sites on the web, such as GitHub, SoundCloud, Dropbox, Netflix, WordPress and many others.


To start the Nginx service, run the following command. Note that this process may fail if the configuration syntax is not OK:

$ sudo systemctl start nginx #systemd

OR

$ sudo service nginx start   #sysvinit


To enable Nginx auto-start at boot time, run the following command:

$ sudo systemctl enable nginx #systemd

OR

$ sudo service nginx enable   #sysv init


How to Show Nginx Command Help ?

To get an easy reference guide of all Nginx commands and options, use following command.

$ systemctl -h nginx

Important Cat Command Examples in Linux

This article covers how to use the Linux cat command. Cat(concatenate) command is very frequently used in Linux. It reads data from the file and gives their content as output. It helps us to create, view, concatenate files.

If you want to add a bit of new text to an existing text file, you use the cat command to do it directly from the command line (instead of opening it in a text editor).

Type the cat command followed by the double output redirection symbol ( >> ) and the name of the file you want to add text to.

Use Shutdown Command in Linux - On Ubuntu | Debian ?

This article covers how to use of shutdown command in Linux with different arguments. Learn more by visit the shutdown man page.

On Unix-like operating systems, the shutdown command shuts down or reboots the system.

The shutdown command brings the system down in a secure way. All logged-in users are notified that the system is going down, and login operations are blocked. It is possible to shut the system down immediately, or after a specified delay.

All processes are first notified that the system is going down by the signal SIGTERM. This gives programs like vi time to save the file being edited, mail and news processing programs a chance to exit cleanly, etc.


Good Linux commands:

  • halt — Stop the computer.
  • poweroff — Stop the computer.
  • reboot — Stop the computer.
  • wall — Send a message to all logged-in users.

Wget Command Examples on Linux Command Line

This article covers different wget command for different operations along with options. Wget is a command line utility in linux to download files from the internet. It provides many features such as downloading multiple files, resuming stopped downloads, limiting the bandwidth, downloading in the background and can be used for taking mirrors of the site. Wget supports HTTP, HTTPS and FTP protocol to connect server and download files.

You can learn more about Wget visit the GNU wget Manual page.


How to Install wget on Ubuntu | Debian ?

If your operating system is Ubuntu, or another Debian-based Linux distribution which uses APT for package management, you can install wget with apt-get:

$ sudo apt-get install wget

Use the Who Command in Debian 10 - How to do it ?

This article covers the who command in Linux along with its some of the useful command line options.

Sometimes, while working on the command line, you might want to know more about logged in users.

There exists a command line utility who which you can use to access this kind of information.

Basically, the who command shows who all are logged in.

Here's its syntax:

$ who [OPTION]... [ FILE | ARG1 ARG2 ]


To access time of last system boot?

For this, use the -b command line option:

$ who -b

Test your Internet Speed through Command-Line in CentOS 8 - How to do it ?

This article covers the different methods through which you can install the Speedtest utility on your CentOS 8 system. 

Also, we have also shown how to test the internet speed through the Speedtest-cli utility and how to generate URLs to share with others.


To Install Speedtest-cli on CentOS 8:

1. Open the terminal to make sure that Python is installed and working properly. Type the following command to check Python version:

$ python --version

If python is not installed on your system then first you will install python on your system. 

For this purpose, you need to run the below-mentioned command on the terminal to install python on CentOS 8.

$ sudo yum install python2

2. Download the speedtest_cli.py file using 'wget' command:

$ wget -O speedtest-cli https://raw.githubusercontent.com/sivel/speedtest-cli/master/speedtest.py

After successfully saved the downloaded file, you will type the following command on the terminal:

$ chmod +x speedtest-cli

Check Disk Usage Using Duf Command-line Utility on Linux

This article covers how To View Disk Usage With Duf On Linux And Unix.

Duf is a command line utility to find disk usage in Linux and Unix-like systems.
It displays the disk usage details in a nice tabular-column and user-friendly layout.
You can even get the disk usage output in JSON format as well.

Features of duf Utility:
1. Easy to use
2. Colorful display
3. Adjust height and width as per your terminal resize movement
4. Sorting data as per our need
5. Filters and groups
6. JSON outputs and more

On DEB-based systems such as Debian, Ubuntu, Linux Mint, download the .deb binary installation file from the releases page and install it using your system's package manager.

$ sudo apt install gdebi
$ sudo gdebi duf_0.3.1_linux_amd64.deb

On RPM-based systems such as RHEL, CentOS, Fedora, download the .rpm binary file and install it using command:

$ sudo rpm -Uvh 
duf_0.3.1_linux_amd64.rpm


To View Disk Usage With Duf On Linux And Unix:
All you have to do is just run the duf command without any options like below:

$ duf

Change Sudo Password Timeout on Ubuntu 20.04 LTS - How to do it ?

This article covers how you can easily change the sudo password timeout by adding a single entry in the sudoers file. If you are using Vi instead of Nano, follow the instructions described here.
You use sudo for some command in the terminal, it asks for the password.

You enter the password, the command runs.
For the subsequent commands, even if they need superuser privileges, you don't need to enter the password again.
After a certain amount of time, when you try to use sudo, it asks for the password again.
It happens because there is a default timeout in Ubuntu and other Linux system for Sudo. In Ubuntu, this default sudo timeout is 15 minutes.
If you think 15 minute is too short or too long you can even change the sudo password timeout in Ubuntu.

To Change sudo password timeout in Ubuntu:
1. Open a terminal (Ctrl+Alt+T) and use the following command:

$ sudo visudo

It will open a file in nano text editor that contains some settings related to sudo.
In here look for the following line:

Defaults        env_reset

Replace above line with this one:

Defaults        env_reset, timestamp_timeout=XX

Where XX is the new timeout value in minutes.
Of course you have to replace the XX with the desired timeout value.
2. Once you are done changing the default sudo password timeout, use Ctrl+X to exit the editor.
It will give you option to save or cancel the changes.

Use Y to save the changes.

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

This article covers how you can install Putty on your Ubuntu OS. Now you can use your Putty SSH client on Linux to connect to remote systems. For more help regarding Putty, visit its user manual.


PuTTY is a popular terminal emulator for Windows, but it is not only limited to Windows operating system. 

Being free and open source, it is popular among Linux users too. PuTTY supports a wide range of protocols such as serial, SSH, Telnet, rlogin, SCP, SFTP etc. 

Sysadmins generally use PuTTY as an SSH and telnet client whereas the Maker community widely uses PuTTY for interfacing with the serial ports on their hardware. 

PuTTY ships with a command line tool named "psftp", the PuTTY SFTP client, which is used to securely transfer files between computers over an SSH connection. 


To install PuTTY on Ubuntu:

1. In order to install Putty, you will need to ensure that the Universe repository is enabled on your Ubuntu system. If it is not already enabled, you can enable it by using the following command in Terminal:

$ sudo add-apt-repository universe

When prompted for the password, enter the sudo password.

2. After enabling the Universe repository, now you can install Putty on your system. Issue the following command in Terminal in order to do so:

$ sudo apt install putty

When prompted for the password, enter the sudo password.

Manage Disk Volumes in RHEL / CentOS Linux - Step by Step Process ?

This article covers how to Manage Disk Volumes in Linux. Disk drives management is one of the most repeated and important tasks for every System Administrator which is considered one of the critical activities. Also, you will be able to increase the disk on your system.

Linux needs at least one partition, namely for its root file system and we can't install Linux OS without partitions.

Once created, a partition must be formatted with an appropriate file system before files can be written to it.


Facts about fdisk Command?

1. fdisk stands for fixed disk or format disk is a cli utility that allow users to perform following actions on disks. 

2. It allows us to view, create, resize, delete, move and copy the partitions.

3. It understands MBR, Sun, SGI and BSD partition tables and it doesn't understand GUID Partition Table (GPT) and it is not designed for large partitions.

4. fdisk allows us to create a maximum of four primary partitions per disk. 

5. One of these may be an extended partition and it holds multiple logical partitions.

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

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 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.

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 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.

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.

Process to install and configure Nagios on Linux ?

This article will guide you on how to install and configure the #Nagios #monitoring solution on Linux. We have also explained how to setup remote hosts for monitoring. Now you can easily monitor the health of #Linux #hosts and the services running on them.

Nagios is an open source monitoring system for computer systems. It was designed to run on the Linux operating system and can monitor devices running Linux, Windows and Unix operating systems (OSes).

Nagios provides complete monitoring of applications and application state – including Windows applications, Linux applications, UNIX applications, and Web applications.

To  install Nagios Plugins and NRPE daemon on the Remote Linux Host:

1. Install Required Dependencies.

2. Create Nagios User.

3. Install the Nagios Plugins.

4. Extract Nagios Plugins.

5. Compile and Install Nagios Plugins.

6. Install Xinetd.

Methods to shutdown Debian 10 from the command line and GUI ?

This article will guide you on how to shut down your Debian 10 system properly using different methods.

If you run a desktop environment, there is usually an option to "log out" available from the #application menu that allows you to shutdown (or #reboot) the system. 

Alternatively you can press the key combination Ctrl+Alt+Del.

To shut down #Linux:

1. To shut down the system from a terminal session, sign in or "su" to the "root" account. 

2. Then type ``/sbin/shutdown -r now''. It may take several moments for all processes to be terminated, and then Linux will shut down.

How To Exit Vim Text Editor Command ?

This article will guide you on how to exit #vim text editor using various options. 1. Open a new or existing file with vim filename . 2. Type i to switch into insert mode so that you can start editing the file. 3. Enter or modify the text with your file. 4. Once you're done, press the escape key Esc to get out of insert mode and back to #command mode. 5. Type :wq to save and exit your file.

How to know Ubuntu version via command line ?

This article will guide you on how to check your Ubuntu version so that you can apply patches and update versions for security and performance reasons. The Process of Checking the #Ubuntu version in the #terminal ? i. Open the terminal using "Show Applications" or use the keyboard shortcut [Ctrl] + [Alt] + [T]. ii. Type the #command "lsb_release -a" into the command line and press enter. iii. The terminal shows the Ubuntu version you're running under "Description" and "Release".

How to Check if your Linux Memory usage is running out

It is vital for you to check if your Linux memory is running low to help your server to stay optimized.