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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.