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GUIDE TO (MOSTLY) HARMLESS HACKING
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GUIDE TO (mostly) HARMLESS HACKING
Microsoft-only version Number 2
Hacking with Win95/NT: Batch File Programming
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by KeyDet89
I figured that, after all of the Happy Hacker Digests
and Guides To (mostly) Harmless Hacking that have
dealt with shell programming, something for Win95 and
NT needed to be addressed.
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Newbie Note: A good resource for batch files is to go to
you local library and look up back issues of PC Magazine.
The older editions, even those published after Win95 came
out, list several useful batch files that you can use
or modify for your own use. WindowsNT Magazine has had
several good articles on scripting languages for NT.
Other excellent sources of information include books from
the library and used bookstores.
Also, visit the alt.msdos.batch newsgroup. If you can't
access newsgroups from your ISP, use your browser to
visit DejaNews at . Or visit
any of the sites listed at the end of this file.
***************************************************
Let's get started. First, keep in mind that batch files
are just series of programs that you would like executed.
The files are made up of commands that already reside on
your machine. If you have several commands that type over
and over, each with specific switches and parameters, you
may want to put them into a batch file. Batch files can
also be used the way aliases are on Un*x...written properly,
you can launch a program from the command line without
having to type it out each time.
A word about editors: You already have two suitable text
editors on your computer...DOS edit, and Notepad. Edit
is fairly simple to use, but you may not be used to it.
Notepad is also easy to use, just remember to save your files
with the correct ".bat" extension so that they will be
recognized as batch files by the command processor.
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Newbie Note: Most of the commands that you will want
to run from batch files will be command line programs.
Check out your windows\command directory to see what
is available. Don't hesitate to look for DOS or Win95
command line programs on the Internet.
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STEP 1 -- "Hello, World"
The first program we will write is the obligatory "Hello World"
program that accompanies every programming language. Simply
save a file called "hello.bat" with the following text:
echo Hello, World!
Now, if you type "hello" at the prompt, you will see the "echo"
line printed at the prompt, then the line "Hello, World!" on the
line below it. To suppress the commands at the prompt, add the
line:
@echo off
as the first line of the file. Now rerun the file.
STEP 2 -- Arguments
Now, let's personalize our program a bit. Change the second line
to:
echo Hello, %1
and run the program by typing:
c:\>hello Johnny
Now we've added arguments, as denoted by the "%1". This refers to
the first argument that is sent to the file. We can send multiple
arguments. To demonstrate, open a file called "args.bat" and type
in the following lines:
@echo off
echo ARGS: %1 %2 %3 %4
echo REV: %4 %3 %2 %1
echo MIXED: %2 %1 %4 %3
Now run the file with at least two arguments (you can use more and
examine the output):
c:\>args hello steve dog rain
STEP 3 -- Redirection
When programming in most languages, there are three references that
you need to be aware of: standard input (STDIN - usually the
keyboard), standard output (STDOUT - the screen), and standard
error (STDERR - also the screen). However, you may not want the
output to go to the screen, you may want it stored in a file. Well,
we can do this fairly easily with something called redirection.
How does this work? Well, when you type in something like:
c:\>attrib /?
to find out what the attrib (attribute) command does, and how
it is used, you see a lot of information on the screen. Try doing
the same thing with the "net" command under Win95, and the info
seems to disappear off the screen! So to send the output of the
command to a file, simply add the greater-than sign and a file
name to the command:
c:\>net /? > net.txt
If you want to add or append information to an already existing
file, use the double-greater-than symbol:
c:\>net view /? >> net.txt
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Cool Trick To Try: I won't be covering HTML programming here,
but here is something to try. There are basic commands that
every web page has...these are the tags that are that are used
to designate the header, title, change colors or fonts, etc.
Write a batch file that takes the output of series of commands,
such as "net", "net view", "net use", "net user", and "net time"
and puts them in an HTML file. That way, you can post it on
the web. You may even go so far as to include links to examples,
etc.
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STEP 4 -- Autoexec.bat
Now is a good time for a word on the King of All Batch Files,
the autoexec.bat file. This is the file that is used by DOS
at boot up, and exists for DOS and Win95 (Win3.1 runs on top of
DOS, and is called from the autoexec.bat file). Use the
autoexec.bat file "to set the characteristics of your devices,
customize the information that MS-DOS displays, and start
memory-resident programs and other applications" (from the
MS-DOS User Guide). Really? Well, given that, you can do all
sorts of interesting things with this file...or any other batch
file.
Note on NT: NT does not use the autoexec.bat file, but there
is a registry key that when set, will enable the parsing of
the autoexec.bat file, reportedly for environment variables.
Gee, I wonder what else it will do...
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Evil Genius Tip: Take a look at the prompt command by typing:
c:\>prompt /?
Play around with different settings. Typing the command to
change the prompt at the current command prompt will change
it for that session...adding the command to the autoexec.bat
file will change if for all sessions.
****************************************************
STEP 5 -- Aliases
You'll notice that when you type:
c:\>notepad somefile.txt
Notepad opens with the file, and in the DOS window, you get
you command prompt back. So if you want a quick way to open
the text files, create a small batch file called "np.bat", with
the lines:
@echo off
notepad %1
Now all you have to do is type "np" and the file name.
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Evil Genius Trick: Here's a handy little way to create a
mini-syslog daemon of your very own...or someone elses.
Create a file called "file.log", or whatever, on the
target computer, in the Windows directory.
HINT: Investigate the "attrib" command, paying particular
attention to the "h" option.
Now, create a batch file that will make entries to file.log.
You might want to have something printed, or just the file
that was opened.
Next, click Start -> Help, and type in "associating" and
display the help on "file types with programs". Change
the associations for ".txt" files to point to your batch
file, and make sure that the last line reads:
notepad %1
If your friend uses Microsoft Word a lot, make the
appropriate changes there, too.
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Neat Trick Tip: If you like the Un*x commands, but don't
want to fool with downloading them, write you own. Create
a batch file called "ls.bat" and use the "dir" commands to
customize the display. Start with:
@echo off
dir %1
Make sure to see what switches are available for the dir
command...
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STEP 6 -- Information Gathering
There are several commands that can be used to gather
information, especially on a networked computer. These
commands can be used to gather information for diagnostic
purposes, as well as being used for other insidious
purposes (no Evil Genius Tips here, I'll leave it up to
your imagination). Start by running the following commands
on your machine while connected to a network or to the
Internet:
nbtstat -c
nbtstat -n
netstat -an
net user (NT only)
net use/config/time/view
arp -a
When you begin to see the type of information that is
available, tailor the commands to your needs, and put
them in a batch file, redirecting the output to a log file
of some sort.
STEP 7 -- More Stuff
I have gathered together some sites that provide more
detailed information on batch file programming. These sources
range all the way from examples to tutorials to post-graduate
theses...so take a look...
BATCH FILE PROGRAMMING SITES
ftp://garbo.uwasa.fi/pc/ts/tsbat53.zip
~http://gearbox.maem.umr.edu/~batch/
~http://www.nc5.infi.net/~wtnewton/batch/index.html
http://purl.oclc.org/net/dirk/batcoll.all
http://purl.oclc.org/net/dirk/batvirus.all
http://www.deltaelectronics.com/tglbatch/
_________________________________________________________
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Copyright 1998 KeyDet89 >. You may forward or post this
GUIDE TO (mostly) HARMLESS HACKING on your Web site as long as you leave
this notice at the end.
___________________________________________________________
Carolyn Meinel
M/B Research -- The Technology Brokers
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