UNIX is a multi-tasking and multi-user computer operating system which was designed to provide good security to the systems. This operating system was developed by some employees of AT&T in Bell Labs. Infact, Linux derives much of its basic design from principles established in Unix. Learning UNIX is essential, whether you are a Linux learner or a perspective hacker and we are here to make your life easy.

Here's a list of free online courses on UNIX:

1. A Basic UNIX Tutorial at Idaho State University

This tutorial comprises fourteen sections, each of which addresses a fundamental aspect of UNIX computing. It concentrates on illustrating the central concepts by providing short explanations, along with examples, and exercises. Topics like directories, text editing, customising the shell, filters, processes, multitasking and accessing UNIX systems are covered effectively.

2. Practical Programming in C at the Massachusetts Institute of Technology

This course provides a thorough introduction to the C programming language, the workhorse of the UNIX operating system. Topics like syntax, grammar, programming techniques, UNIX signals, hash tables, external libraries and synchronisation are covered effectively.

3. Practical Unix at Stanford University

A practical introduction to using the Unix operating system with a focus on Linux command line skills available through video lectures. Topics like grep and regular expressions, ZSH, Vim and Emacs, basic and advanced GDB features, permissions, working with the file system, revision control, Unix utilities, environment customisation, and using Python for shell scripts are covered effectively.

4. Systems Programming and UNIX at the University of Arizona

Provides UNIX information actually taught on campus University of Arizona. Contains links to PDF lecture slides, exams and solutions and example assignments. You also get the names of the textbooks used on campus, which are optional to buy. However, won't give you any actual credit.

5. Unix—the Bare Minimum at the University of California - Davis

This PDF tutorial trains students in UNIX basics by using explanatory text with example commands. Topics like special names for some directories, creating directories, text editors, file commands, moving files to other directories, pipes and redirection are covered effectively.

6. UNIXhelp for Users at the University of Mississippi

Students are proviede with a manual index or glossary to research terms that they might find diificult to understand. Topics like looking-up commands, understanding processes, program development tools, editing text files, writing shell scripts, managing processes and file manipulation utilities are covered effectively.

7. UNIX Tutorial at the University of Utah
Students are provided with a reference manual to find specific command summaries. Topics like making and removing directories, creating short files, printing files, examining files, changing directories and imputing simple commands are covered effectively.

8. UNIX Tutorial for Beginners at the University of Utah

Provides students with eight UNIX tutorials outlining step-by-step procedures and codes. Topics like files and directories, copying files, redirection, killing a process, useful commands, source codes and variables are covered effectively.

An SQL injection attack is a code injection attack that is used to exploit web applications and websites. It is one of the most common methods for hackers to get into your system. Learning such attacks are important for anyone looking to perform their own exploits. Here are 10 of the most powerful tools that aid in performing SQL Injection attacks.

1. BSQL Hacker

This is a useful tool for both experts and beginners that automates SQL Injection attacks on websites.

2. The Mole

This is an SQL Injection tool that uses the union technique or the boolean query-based technique.

3. Pangolin

This is a penetration testing tool developed by NOSEC. It is aimed at detecting and exploiting SQL injection vulnerabilities on websites.

4. Sqlmap

This is an open source penetration testing tool that security professionals can use. Like the BSQL Hacker tool, this one also automates SQL Injection attacks.

5. Havij

This is an automated SQL injection tool that can be used by penetration testers in order to detect vulnerabilities in web applications and exploit them.

6. Enema SQLi

This is a dynamic penetration testing tool for professionals. It is an auto-hacking software.

7. Sqlninja

This is a tool targeted at exploiting SQL injection vulnerabilities. It uses the Microsoft SQL server as its back end.

8. sqlsus

Written using the Perl programming language, this is an open source penetration testing tool for MySQL Injection and takeover.

9. Safe3 SQL Injector

This is a powerful penetration testing tool, which automates the process of detecting and exploiting SQL Injection vulnerabilities.

10. SQL Poizon

This tool includes php , asp , rfi , lf dorks that can be used for penetration testing.

Replace word or text in a file with command line in Windows

Replace word or text in a file with command line in Windows


powershell -Command "(gc BeforeReplace.txt) -replace 'OrginalTextToBeReplaced', 'NewTextToBeReplaced' | Out-File -encoding ASCII AfterReplace.txt"

Install Telnet service in Windows using Command Line

Install Telnet service in Windows using Command Line

You can use below command as admin in your CMD


pkgmgr /iu:”TelnetClient”

Change or Create another RDP Port on Windows OS using Command Line

Change or Create another RDP Port on Windows OS using Command Line

This have two benefits:

1- It reduce the random scanning on the default port 3389 and avoiding the brute force attacks attempts.

2-Secondly you may have faced an issue in your internet home connection that the ISP is unintentionally blocking the outgoing traffic to destination port 3389, so in this scenario you could open another port on the server for RDP and you would be able to RDP to it easily.

Let us start :

1- Change the current Port:

We will change the port from 3389 to 3388 by command line:

REG ADD HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp\ /v PortNumber /t REG_DWORD /d 0xd3c‬ 

This should change it 

To verify, you can either telnet localhost 3388 or execute below query against the registry value of the PortNumber

REG QUERY "HKLM\System\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp-3388" /v PortNumber

Now you would need to allow it in Windows firewall,

You can execute below command in your cmd

netsh advfirewall firewall add rule name="RDP UDP 3388 ports" protocol=UDP dir=in localport=3388 action=allow

netsh advfirewall firewall add rule name="RDP TCP 3388 ports" protocol=TCP dir=in localport=3388 action=allow

1- Create new Port:

We will follow few steps, below is the summary for these steps:

  a. Exporting current Port Value

  b. Change the Value Name

  c. Add the new Reg file to registry silently 

  d. Then change the port for the new Value that was created in above steps.

Below are the commands used in CMD as admin

REG EXPORT  "HKLM\System\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp" RDP-Tcp-3388.reg

powershell -Command "(gc RDP-Tcp-3388.reg) -replace 'RDP-Tcp', 'RDP-Tcp-3388' | Out-File -encoding ASCII RDP-Tcp-3388.reg"

regedit /s RDP-Tcp-3388.reg

REG ADD "HKLM\System\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp-3388" /v PortNumber /t REG_DWORD /d 0xd3c /f

You need also to allow the port in Windows Firewall

netsh advfirewall firewall add rule name="RDP UDP 3388 ports" protocol=UDP dir=in localport=3388 action=allow

netsh advfirewall firewall add rule name="RDP TCP 3388 ports" protocol=TCP dir=in localport=3388 action=allow

RDP CredSSP Issue: an authentication error has occurred

If you encountered this error an authentication error has occurred

You could try to execute below command as administrator:

REG  ADD HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System\CredSSP\Parameters\ /v AllowEncryptionOracle /t REG_DWORD /d 2

And try again,

8 Of The best APIs For Coders & Developers

APIs form an integral part of any coder/developer's daily life. While there are many good ones mushrooming the internet, some websites especially cater to a developer's varied needs, thereby making their life easier. We have compiled here a list of 8 good APIs for coders/developers.

1.Twilio
Twilio powers the future of business communications, enabling phones, VoIP, and messaging to be embedded into web, desktop, and mobile software.

2.Factual
Factual’s location platform enriches mobile location signals with definitive global data, enabling personalised and contextually relevant mobile experiences. Built from billions of inputs, the data is constantly updated by Factual’s real-time data stack.

3.Filepicker.io Connect your app to everything from Dropbox to Gmail in just 2 lines of code and let the Filepicker.io handle the mess of uploading files - it gives you a clean, short URL that is easy to store and read from.

4.Context.IO
Context.IO is a REST email API that makes it easy and fast to integrate your users' email data in your application.

5.Embedly
With the Embedly API you can get great content, make it beautiful, and understand how people use it.

6.PubNub
The PubNub Realtime Network powers thousands of apps, streaming more than 3 million messages a second to over 200 million devices a month.

7.Mailgun
Powerful APIs that allow you to send, receive and track email effortlessly.

8.Stripe
A beautiful, optimised, cross-device payment form with support for single click payments.