18 July, 2015

How to Add a Favicon to My Site


First of All What is meant by FAVICON?

            A favicon is a graphic image (icon) associated with a particular Web page and/or Web site. Many recent user agents (such as graphical browsers and newsreaders) display them as a visual reminder of the Web site identity in the address bar or in tabs.

           This document does not discuss in detail how to create a favicon image. However, the format for the image you have chosen must be 16x16 pixels or 32x32 pixels, using either 8-bit or 24-bit colors. The format of the image must be one of PNG (a W3C standard), GIF, or ICO.

Use of a rel attribute value:

           The first approach for specifying a favicon is to use the rel attribute value "icon". In this HTML 5 example, the favicon identified via the URI http://example.com/myicon.png as being a favicon:


<!DOCTYPE html>
<head>
<title>Your Website Name</title>
<link rel="icon"
type="image/png" href="http://example.com/myicon.png"> […] </head> […] </html>



The XHTML 1.0 version looks very similar:

<!DOCTYPE html>

   <head>
   <title>Your Website Name</title>
<link rel="icon" type="image/png" href="/somewhere/myicon.png" /> […] </head> […] </html>


     In above step in link tag,the href refers to the location and filename of your favicon."href="/somewhere/myicon.png"

19 August, 2014

How hackers hack Facebook Account & How to stop them?


Facebook is, undoubtedly, the most popular social networking website with more than 500 million active users. Due to its popularity, many hackers (or should I say crackers?) are actively involved in hacking Facebook accounts of unsuspecting users. This article outlines the many strategies that such hackers use to gain access to Facebook accounts of hundreds of users each day and how you can stop them from hacking your account.

hack facebook account
Facebook is one of the prime target of hackers!

Email Address Hack

I have always been puzzled by Facebook's leniency in this matter. All a hacker needs to do is know your email address and he will be displayed  a confirmation showing your name even if he enters the wrong password. How easily a hacker can then hack your Facebook account if he 'guesses' your password (if you use a weak password) or answers your security question! This is something I hope Facebook improves on quickly. Until Facebook does so, here are some tricks you can use to protect yourself from this vulnerability.

How to safeguard your Email Address?
Just follow these steps:-

  1. Hide your Email Address from everyone by going to Edit Profile>Contact Information>Clicking on the icon beside your email address> checking 'Only Me'.
  2. Change your primary email address to a one that is only known to you by going to Account Settings>Email> and changing your primary email to the new one (known only to you) and removing your previous email address.
  3. For additional security, when in Account Settings, check 'Secure browsing' and 'Send me an email when a new computer or mobile device logs into this account' and click Save.

hack facebook
A hacker at work!

Phishing

Phishing is one of the easiest ways to trick users into giving out their login credentials. All a hacker does is setup a webpage similar in design to that of the Facebook homepage, attach a server sided script to track the username and password entered and store it in a log. Sending people emails stating that someone tagged a photo of them on Facebook in the same format as Facebook and giving a link below to the phishing website further reduces the chances of it being detected as a fake. Sometimes, spam Facebook apps, like those promising to tell who viewed your Facebook profile, automatically post links to phishing websites. A new trend amongst phishers is creating Facebook look-a-like widgets for stealing user's login credentials.

How to prevent yourself from being phished?
At all costs, avoid clicking on suspicious links. Moreover, always check the URL in the address bar before signing in. Avoid logging in through various "Facebook widgets" offered by websites and blogs. Instead, use Facebook's homepage to sign in. Always try to use Safe Search while searching. If you do manage to get phished, report the website so that others may get a warning before visiting it.


hack facebook password

Keylogging through Keyloggers

Keylogger is a type of computer virus that tracks key strokes. Keyloggers can be installed remotely on a computer system by a cracker to record all the activity that is going on the victim's computer. Keylogging gets more easy if the hacker has physical access to the victim's computer.

How to stop keyloggers?
Install a good antivirus and update it frequently. Do not click on suspicious links and avoid downloading illegal software. Also, avoid installing free toolbars and other such spam software. Always scan third-person's flash and pen drives before using them on your computer.

Social Engineering

Social engineering involves using any trick to fool the user into making himself vulnerable to exploits. This could involve anything from sending spoof emails, pretending to be from Facebook, telling you to change your password to 12345678 to a hacker maliciously getting out the answer to your Security Question in a friendly chat or discussion.

How to prevent yourself from being socially engineered?
Stay aware during chats and discussions. Use a tough security question, preferably one whose answer you would never disclose to anyone. Moreover, Facebook, or any other company for that matter, will never ask you to change your password to 12345678 or do something as silly as asking you to send out your login details to prove that you are an active user. Always think before taking actions and your e-life on Facebook will be safe from hackers looking to hack Facebook accounts.

Google Tricks, Easter Eggs & Secrets


Google's engineers love to hide some pretty cool tricks at the most unexpected places. Add to that Google's policy of giving 20% of working time to its engineers to do what they want, and you have a search engine filled with lots of entertaining Easter eggs and tricks.

Sadly, most of these tricks are still a secret, but every now and then, Google employees leak these cool insider pranks and the whole world gets to know about them. Here, I have created a list of all such known Google tricks and Easter eggs that are still "working."
Google Tricks

Google in 1998
Search Google for "Google in 1998" and you will be taken to the past to a search results page that shows how Google looked in 1998.

Kerning
Kerning means adjusting the spacing between characters. So, how would you expect Google to describe it? Literally, off course. When you search Google for Kerning, the spacing of the word Kerning is changed as compared to that of other words. This only works with personalized results disabled.

Conway's Game Of Life
Conway's Game Of Life is a game that indicates how cellular life evolves based on the initial configuration. If you search Google for Conway's Game of Life, you will get a results page with the game running in the background.

Jason Isaacs
Just search for Jason Isaacs and Google will return a page saying Hello to him. This only works on Google UK. This is a reference to Kermode and Mayo's Film reviews which greets Jason with hello every week.

Bacon Number {Actor Name}
Kevin Bacon is a famous hollywood actor who was quoted as saying that he has worked with everybody in hollywood or somebody who has worked with them in 1994. This led to many websites being launched about his claim in 2007. Bacon seeing this immense response launched a charitable website called Six Degrees, which is based on a theory that everyone in hollywood has worked with Kevin Bacon through a chain of six acquaintances or less. An actor gets as many degrees as he is distant from Kevin Bacon's movies in terms of people in the chain of acquaintances.

Google too has now involved Six Degrees of Bacon in its search results. For example, searching Google for Bacon Number Johnny Depp gives Depp's Bacon number to be 2.

Google knows how to celebrate the holidays
Searching Google for a holiday will make Google return a page decorated with items representing that holiday. For example, searching Google for Christmas returns a page decorated with Christmas lights. This also works for Kwanzaa, Hanukkah, Halloween and Festivus. These Easter Eggs based on a festival are only activated when that festival is near.

Zerg Rush
Search Google for Zerg Rush and you will see the O's of Google attacking the search results page. They will attacking every result one by one. There is a health bar which indicates how injured a search result is. You can also kill these O's by clicking on them. They also have health bars which indicates their health. You get points on the basis of how many O's you kill. The aim of this game is to beat as many O's as possible.

Zerg Rush Google Easter Egg

Askew or Tilt
Ever had the chance of searching Google for Askew or Tilt? If you have, then you already know what comes up. If you haven't, do it now and you will see the search results page literally tilt to give you a better idea of what these words mean. This will work only if you use latest browsers which support HTML5 and CSS3. So, Internet Explorer users, use Firefox, Google Chrome or Safari for a while to use this.

Do a barrel roll
Google Tricks & Easter Eggs
'Do a barrel roll' in its true sense means to do a 360 degree spin. Google takes practical demonstrations way too seriously for this one and literally spins the search results page to give you a clearer idea of the meaning of this phrase. Don't believe me? Go search Google for Do a barrel roll now and see your world turn around.

This Easter egg is apparently a tribute to Star Fox, a video game series developed by Nintendo, because searching Google for Z or R Twice also does the barrel roll, just like in Star Fox. Manybloggers interpreted a lot of different things from this, but Google clarified that this fun trick was created by a Google Engineer solely for the purpose of entertaining users along with showing the power of new HTML5 and CSS3 technologies. Like the previous Easter egg, this will only work in modern browsers.

Binary, Octal and Hexadecimal Number systems
Another one of those literal Google Easter eggs. If you search Google for "Binary""Octal" or"Hexadecimal" (without quotes) with Search Plus Your World disabled, Google will show the number of results in the same number system. For example, searching Google for hexadecimal will return the number of results like in the image below.

Octal, Binary & Hexadecimal

Recursion
The "Did you mean?" feature of Google often helps many users to get to the right results when they type something different from what they intended to search. If you search Google for recursion, the same feature takes you to an endless loop of clicks all linking to the same results page thereby completing recursion, which occurs when something calls itself. Seriously geeky.

Recursion Google Easter egg

Anagram
Another one of those "Did you mean?" Easter eggs. Search Google for Anagram and Google will instantly ask whether you meant "Nag A Ram" which is one of the anagrams of the word "anagram." Google really shows their word-playing skills with this one.

Asking Google to define Anagram makes Google ask if you meant nerd fame again.

ASCII Art
Are you a fan of ASCII art? Google surely is. Search Google for ASCII art and Google will greet you with a search results page having an ASCII version of the Google logo at the place where normal logo should have been. This Easter egg does not work anymore. When it did work, it looked like the image given below.
ASCII art Google Easter Egg

Google Calculator Easter Eggs: The loneliest number
Google Secrets
Do you know which is the loneliest number? Ask Google Calculator. Search Google for the loneliest number and the in-search Google Calculator will give one as the answer, which apparently is a tribute to the Harry Nilsson's song "One."

Once in a Blue Moon
Google Tricks Easter Eggs
Ever wondered how much is 'once in a blue moon'? You must have heard this phrase often but Google calculator will give you the exact value of this phrase and surprisingly, it denotes frequency rather than time. Go search Google for this to get "1.16699016 × 10-8 hertz" as the answer.

The number of horns on a unicorn
Want to know the number of horns on a unicorn? Google calculator can help. Searching Google for the number of horns on a unicorn will give 1 as the answer.

Answer to the Ultimate Question of Life, the universe and everything
Google Easter eggs
Google is omniscient. Even the "answer to the ultimate question of life, the universe and everything" is known to Google. Just search Google for the above phrase and Google calculator will give you an answer. What are you waiting for? Just go to Google and find the true meaning of life.

[Pause to give you the time to search]

Surprised by the answer (42)? This is a reference to The Hitchhiker's Guide to the Galaxy, a popular novel based on a radio show (by the same name) of the late seventies. Google engineers surprised you with these tricks, didn't they?

Disable USB ports on Windows PC via Registry


With this trick, you can disable access to your USB(Universal Serial Bus) ports on your Windows based PC to prevent people from taking out data without permission or spreading viruses through the use of USB (pen and flash) drives.

To use this trick to disable USB ports, follow the steps given below:-

  1. Click on Start.
  2. Click on Run. If you cannot find RUN, type it in the search box.
  3. Type "regedit" without quotes. This will launch the Registry Editor.
  4. Navigate to  HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\usbstor.
  5. In the work area, double click on Start.
  6. In the Value Data box, enter 4.
  7. Click on OK.
  8. Close Registry Editor and refresh your desktop.
  9. To re-enable access to your USB ports, enter 3 in the Value Data box in Step 6.

Disable access to USB ports on your PC using Registry Editor

Try it yourself to make your PC invulnerable from data theft and malware which spread through USB ports. This works on Windows XP, Windows Vista, Windows 7 and Windows 8.

Note: This trick also disables access to your USB connected peripheral devices. So, do not use it if you have USB connected keyboard and mouse.

Create a Harmless Funny Virus with Notepad-Continuously eject CD/DVD drives

This VBS trick will create a code which will continuously eject all your connected Optical drives. If you put them back in, it will pop them out again. Copy this code and paste it in Notepad as Virus.vbs or *.vbs.

Notepad Virus
Set oWMP = CreateObject("WMPlayer.OCX.7")
Set colCDROMs = oWMP.cdromCollection
do
if colCDROMs.Count >= 1 then
For i = 0 to colCDROMs.Count - 1
colCDROMs.Item(i).Eject
Next
For i = 0 to colCDROMs.Count - 1
colCDROMs.Item(i).Eject
Next
End If
wscript.sleep 5000
loop

Double click to open this file and you will be impressed by this awesome trick.

VBS Trick - Make Your Keyboard Type Message Continuously


This VBS trick can make any of your friend's keyboard type any message continuously. Open Notepad, copy the code given below and save the file as Tricks.vbs or *.vbs. You will need to restart your computer to stop this. Try this after closing all important programs.

Set wshShell = wscript.CreateObject("WScript.Shell")
do
wscript.sleep 100
wshshell.sendkeys "This is a Virus. You have been infected."
loop
Send this file to your friends as an email attachment to see the fun.

17 August, 2014

Run Line Commands

Run line commands can be very useful some times, its better to know them here are all the commands that i know u might find them usefull too Commands are same for Windows xp pro and home 

Run Line Commands


These are GUI applications that can be opened from the run line.
These applications are not located in the C:\windows\system32\ directory, the
keys for these applications are located in the registry under: 
HKLM\software\microsoft\windows\currentversion\app paths BCKGZM.EXE – Backgammon
CHKRZM.EXE – Checkers
CONF.EXE – NetMeeting
DIALER.EXE – Phone Dialer
HELPCTR.EXE – Help and Support
HRTZZM.EXE – Internet Hearts
HYPERTRM.EXE – HyperTerminal
ICWCONN1.EXE – Internet Connection Wizard
IEXPLORE.EXE – Internet Explorer
INETWIZ.EXE – Setup Your Internet Connection
INSTALL.EXE – User’s Folder
MIGWIZ.EXE – File and Settings Transfer Wizard
MOVIEMK.EXE – Windows Movie Maker
MPLAYER2.EXE – Windows Media Player Version 6.4.09.1120
MSCONFIG.EXE – System Configuration Utility
MSIMN.EXE – Outlook Express
MSINFO32.EXE – System Information
MSMSGS.EXE – Windows Messenger
MSN6.EXE – MSN Explorer
PBRUSH.EXE – Paint
PINBALL.EXE – Pinball
RVSEZM.EXE – Reversi
SHVLZM.EXE – Spades
TABLE30.EXE – User’s Folder
WAB.EXE – Windows Address Book
WABMIG.EXE – Address Book Import Tool
WINNT32.EXE – User’s Folder
WMPLAYER.EXE – Windows Media Player
WRITE.EXE – Wordpad

These .EXE files reside in (c:\windows\system32\) or (c:\windows\) directory.
ACCWIZ.EXE – Accessibility Wizard
CALC.EXE – Calculator
CHARMAP.EXE – Character Map
CLEANMGR.EXE – Disk Space Cleanup Manager
CLICONFG.EXE – SQL Client Configuration Utility
CLIPBRD.EXE – Clipbook Viewer
CLSPACK.EXE – Class Package Export Tool
CMD.EXE – Command Line
CMSTP.EXE – Connection Manager Profile Installer
CONTROL.EXE – Control Panel
DCOMCNFG.EXE – Component Services
DDESHARE.EXE – DDE Share
DRWATSON.EXE – Doctor Watson v1.00b
DRWTSN32.EXE – Doctor Watson Settings
DVDPLAY.EXE – DVD Player
DXDIAG.EXE – DirectX Diagnostics
EUDCEDIT.EXE – Private Character Editor
EVENTVWR.EXE – Event Viewer
EXPLORER.EXE – Windows Explorer
FREECELL.EXE – Free Cell
FXSCLNT.EXE – Fax Console
FXSCOVER.EXE – Fax Cover Page Editor
FXSEND.EXE – MS Fax Send Note Utility
IEXPRESS.EXE – IExpress 2.0
LOGOFF.EXE – System Logoff
MAGNIFY.EXE – Microsoft Magnifier
MMC.EXE – Microsoft Management Console
MOBSYNC.EXE – Microsoft Synchronization Manager
MPLAY32.EXE – Windows Media Player version 5.1
MSHEARTS.EXE – Hearts
MSPAINT.EXE – Paint
MSTSC.EXE – Remote Desktop Connection
NARRATOR.EXE – Microsoft Narrator
NETSETUP.EXE – Network Setup Wizard
NOTEPAD.EXE – Notepad
NSLOOKUP.EXE – NSLookup Application
NTSD.EXE – Symbolic Debugger for Windows 2000
ODBCAD32.EXE – ODBC Data Source Administrator
OSK.EXE – On Screen Keyboard
OSUNINST.EXE – Windows Uninstall Utility
PACKAGER.EXE – Object Packager
PERFMON.EXE – Performance Monitor
PROGMAN.EXE – Program Manager
RASPHONE.EXE – Remote Access Phonebook
REGEDIT.EXE – Registry Editor
REGEDT32.EXE – Registry Editor
RESET.EXE – Resets Session
RSTRUI.EXE – System Restore
RTCSHARE.EXE – RTC Application Sharing
SFC.EXE – System File Checker
SHRPUBW.EXE – Create Shared Folder
SHUTDOWN.EXE – System Shutdown
SIGVERIF.EXE – File Signature Verification
SNDREC32.EXE – Sound Recorder
SNDVOL32.EXE – Sound Volume
SOL.EXE – Solitaire
SPIDER.EXE – Spider Solitaire
SYNCAPP.EXE – Create A Briefcase
SYSEDIT.EXE – System Configuration Editor
SYSKEY.EXE – SAM Lock Tool
TASKMGR.EXE – Task Manager
TELNET.EXE – MS Telnet Client
TSSHUTDN.EXE – System Shutdown
TOURSTART.EXE – Windows Tour Launcher
UTILMAN.EXE – System Utility Manager
USERINIT.EXE – My Documents
VERIFIER.EXE – Driver Verifier Manager
WIAACMGR.EXE – Scanner and Camera Wizard
WINCHAT.EXE – Windows for Workgroups Chat
WINHELP.EXE – Windows Help Engine
WINHLP32.EXE – Help
WINMINE.EXE – Minesweeper
WINVER.EXE – Windows Version Information
WRITE.EXE – WordPad
WSCRIPT.EXE – Windows Script Host Settings
WUPDMGR.EXE – Windows Update

The following are Control Panel applets that can be run from the run line.
They are located in the c:\windows\system32 directory, and have the file type
extension “.CPL”.
ACCESS.CPL – Accessibility Options
APPWIZ.CPL – Add or Remove Programs
DESK.CPL – Display Properties
HDWWIZ.CPL – Add Hardware Wizard
INETCPL.CPL – Internet Explorer Properties
INTL.CPL – Regional and Language Options
JOY.CPL –                 Game Controllers
MAIN.CPL –               Mouse Properties
MMSYS.CPL –           Sounds and Audio Device Properties
NCPA.CPL –              Network Connections
NUSRMGR.CPL –    User Accounts
ODBCCP32.CPL –   ODBC Data Source Administrator
POWERCFG.CPL –  Power Options Properties
SYSDM.CPL –          System Properties
TELEPHON.CPL –   Phone and Modem Options
TIMEDATE.CPL –    Date and Time Properties


The following are Microsoft Management Console Snap-ins that can be opened from
the run line. These applications have the file type extension “.MSC”.


CERTMGR.MSC – Certificates
CIADV.MSC –         Indexing Service
COMPMGMT.MSC – Computer Management
DEVMGMT.MSC – Device Manager
DFRG.MSC – Disk Defragmenter
DISKMGMT.MSC – Disk Management
EVENTVWR.MSC – Event Viewer
FSMGMT.MSC – Shared Folders
LUSRMGR.MSC – Local Users and Groups
NTMSMGR.MSC – Removable Storage
NTMSOPRQ.MSC – Removable Storage Operator Requests
PERFMON.MSC – Performance Monitor
SERVICES.MSC – Services
WMIMGMT.MSC – Windows Management Infrastructure


Cmd Commands most using hacking Commands

CMD commads

Cmd/Dos Prompt Commands most using hacking Commands

full RUN commands and COMMAND PROMPT commands



Accessibility Controlsaccess.cpl
Add Hardware Wizardhdwwiz.cpl
Add/Remove Programsappwiz.cpl
Administrative Toolscontrol admintools
Automatic Updateswuaucpl.cpl
Bluetooth Transfer Wizardfsquirt
Calculatorcalc
Certificate Managercertmgr.msc
Character Mapcharmap
Check Disk Utilitychkdsk
Clipboard Viewerclipbrd
Command Promptcmd
Component Servicesdcomcnfg
Computer Managementcompmgmt.msc
timedate.cplddeshare
Device Managerdevmgmt.msc
Direct X Control Panel (If Installed)*directx.cpl
Direct X Troubleshooterdxdiag
Disk Cleanup Utilitycleanmgr
Disk Defragmentdfrg.msc
Disk Managementdiskmgmt.msc
Disk Partition Managerdiskpart
Display Propertiescontrol desktop
Display Propertiesdesk.cpl
Display Properties (w/Appearance Tab Preselected)control color
Dr. Watson System Troubleshooting Utilitydrwtsn32
Driver Verifier Utilityverifier
Event Viewereventvwr.msc
File Signature Verification Toolsigverif
Findfastfindfast.cpl
Folders Propertiescontrol folders
Fontscontrol fonts
Fonts Folderfonts
Free Cell Card Gamefreecell
Game Controllersjoy.cpl
Group Policy Editor (XP Prof)gpedit.msc
Hearts Card Gamemshearts
Iexpress Wizardiexpress
Indexing Serviceciadv.msc
Internet Propertiesinetcpl.cpl
IP Configuration (Display Connection Configuration)ipconfig /all
IP Configuration (Display DNS Cache Contents)ipconfig /displaydns
IP Configuration (Delete DNS Cache Contents)ipconfig /flushdns
IP Configuration (Release All Connections)ipconfig /release
IP Configuration (Renew All Connections)ipconfig /renew
IP Configuration (Refreshes DHCP & Re-Registers DNS)ipconfig /registerdns
IP Configuration (Display DHCP Class ID)ipconfig /showclassid
IP Configuration (Modifies DHCP Class ID)ipconfig /setclassid
Java Control Panel (If Installed)jpicpl32.cpl
Java Control Panel (If Installed)javaws
Keyboard Propertiescontrol keyboard
Local Security Settingssecpol.msc
Local Users and Groupslusrmgr.msc
Logs You Out Of Windowslogoff
Microsoft Chatwinchat
Minesweeper Gamewinmine
Mouse Propertiescontrol mouse
Mouse Propertiesmain.cpl
Network Connectionscontrol netconnections
Network Connectionsncpa.cpl
Network Setup Wizardnetsetup.cpl
Notepadnotepad
Nview Desktop Manager (If Installed)nvtuicpl.cpl
Object Packagerpackager
ODBC Data Source Administratorodbccp32.cpl
On Screen Keyboardosk
Opens AC3 Filter (If Installed)ac3filter.cpl
Password Propertiespassword.cpl
Performance Monitorperfmon.msc
Performance Monitorperfmon
Phone and Modem Optionstelephon.cpl
Power Configurationpowercfg.cpl
Printers and Faxescontrol printers
Printers Folderprinters
Private Character Editoreudcedit
Quicktime (If Installed)QuickTime.cpl
Regional Settingsintl.cpl
Registry Editorregedit
Registry Editorregedit32
Remote Desktopmstsc
Removable Storagentmsmgr.msc
Removable Storage Operator Requestsntmsoprq.msc
Resultant Set of Policy (XP Prof)rsop.msc
Scanners and Camerassticpl.cpl
Scheduled Taskscontrol schedtasks
Security Centerwscui.cpl
Servicesservices.msc
Shared Foldersfsmgmt.msc
Shuts Down Windowsshutdown
Sounds and Audiommsys.cpl
Spider Solitare Card Gamespider
SQL Client Configurationcliconfg
System Configuration Editorsysedit
System Configuration Utilitymsconfig
System File Checker Utility (Scan Immediately)sfc /scannow
System File Checker Utility (Scan Once At Next Boot)sfc /scanonce
System File Checker Utility (Scan On Every Boot)sfc /scanboot
System File Checker Utility (Return to Default Setting)sfc /revert
System File Checker Utility (Purge File Cache)sfc /purgecache
System File Checker Utility (Set Cache Size to size x)sfc /cachesize=x
System Propertiessysdm.cpl
Task Managertaskmgr
Telnet Clienttelnet
User Account Managementnusrmgr.cpl
Utility Managerutilman
Windows Firewallfirewall.cpl
Windows Magnifiermagnify
Windows Management Infrastructurewmimgmt.msc
Windows System Security Toolsyskey
Windows Update Launcheswupdmgr
Windows XP Tour Wizardtourstart
Wordpadwrite
Calculation on command Prompt ! u knew this???

The command processor CMD.EXE comes with a mini-calculator that can perform simple arithmetic on 32-bit signed integers:

C:\>set /a 2+2
4
C:\>set /a 2*(9/2)
8
C:\>set /a (2*9)/2
9
C:\>set /a “31>>2″
7