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Better living... through (mostly) Harmless Hacking
Unix Edition
Jan. 25, 2000
See the Happy Hacker web site at http://www.happyhacker.org
Firewall gives you problems? Try http://happyhacker.org

*** Editor's Comments

Hmm... one week late. My motherboard kinda had a fit this past week... my
IDE controller wasn't working... and most of your emails were on my hard
drive.... well... here's the digest, better late than never.

*** Readers' Submissions

b2329@gateway.net asks:

I am new to the world of Linux; Unix. I do have some experience programming
in C, C++ etc. But I have been becoming increasingly interested in Linux. My
place of employment is getting rid of several old PCs and I have first dibs
on a few, which I plan to install Linux to play around with. Can you suggest
a version of Linux for beginners? Also are there any good tutorials out
there? What are they? I am interested in learning from the ground up, unlike
some people I know who like shortcuts and don't know a bit of programming.

Can you also suggest an extreme version of Linux? I tend to learn things I'm
interested in extremely fast and will no doubt be ready in a couple of

You can probably guess what my intentions are for learning Linux since I am
addressing this to you instead of some Tech person, please keep this in mind
when making your suggestions.

7hanks [sic] in advance for any response!

[Editor: I'm not sure what exactly you mean by an "extreme" version of
linux. And since we're not tech people here (at least, you say we're not), I
can only guess at what your last paragraph means. As far as Linux
distro's... I put out a collection of some of the responses to the question:
"what's your favorite *nix and why?". CNet had a nice summary a while
back... check them... and if you really are interested in learning from the
ground up, it won't matter what distro you have... you can get sent to jail
from any of them :)]


Andy Garner <siliconmonk@hotmail.com> asks:

I was wondering what books that you would suggest for a person just starting
in Unix with a basic programing backround? I subscribe to your newsletter
and I often find myself with basic questions regarding Unix itself. If you
could suggest some texts I would be much appreciative.


[Editor: Anything by O'Reilly (the ones with the animals on the cover). The
have books for everyone from the advanced beginner to true wizards. If you
need something more basic... you can try the more mainstream (read: watered
down) titles from SAM's, Que, etc... just remember two things: fat does not
equal lots of info, and the content is inversely proportional to the colors
on the front cover. I'd get a copy of "Essential System Administration"
(O'Reilly), and work your way through it... that's probabaly your best


Ktinga <ktinga@unm.edu> sent:


I have a csh prompt (which will work with tcsh). I use it
everwhere and is my favorite

set shost=`basename $HOST .your.domain`
set prompt = $shost"$cwd> "
alias cd 'set old=$cwd; chdir \!*; set prompt=$shost"$cwd> "'

Basename will strip off a string of text that you specify from the
end of another string of text you give it. In this case, .your.domain is
stripped off from the $HOST enviroment variable, which will include said
smaller string of text.
The second line will set the prompt to the machine name and the
Current Working Directory (cwd) enviornment variable. I find this helpful
for admining and keeping track of wher I am on the filesystem.
The third line is also important and ensures that the prompt is
kept up to date. You can configure the prompt to do all kinds of things,
like display the time and date, even read a fortune. However, prompts can
get sort of long after a while.
I am not certain who wrote the above three lines of code. This
code appeared in a .login file that was freely passed among students at a
up and coming research university in the southwest. I do not know who
originally coded this. However, suffice it to say, it was not me.

As for the gentlemen (I suppose) with the radio lan...I too have a
small LAN inside my home and found that just using BIND v.8 worked just
fine using standard ethernet over normal 10/100 cabeling and hubs
(switches are too expensive for me). You may also wish to consider that,
too. You can use a certain range of IP numbers that have been designated
for private use only and are not used on the internet at all. I believe
that they fall within the range of 171 to 191 or something like that. I'm
sure it's included in an RFC somewhere.
You can retrieve the BIND software at


O'Rielly's _DNS and BIND_ by Albitz and Liu is an excellent
resource. There are also numerous FAQ's at


As for radio ethernet, you'll find that the speed gets to be
annoyingly slow and that the security is pretty bad. RF signals are
relatively easy to intercept, especially since they can be intercepted
without the transmitter or reciever realizing that the interception is
occuring. All you need is a scanner. A common feature of radio ethernet is
to use frequency-hopping. This technique varries the transmission
frequency rapidly; this makes it difficult for someone to listen in. Most
vendors also offer encryption options, like DES. However, it can slow down
the transmission speed for the process of encryption/decryption.

[Editor: Thanks for the multiple posts. The most useful unassigned IP's are
the Class C's in the 192.168.x.x range. There's also an unassigned class B,
and I think even a class A, but I'm not certain about that. As far as
snooping on RF ethernet... does anyone have any knowledge of such a task?
I'm sure a scanner should do it... or is it more complex. Do they run trunks
(like many PD + FD's do these days)? It might be an interesting topic to
explore... maybe on the antionline mailing list directly.]


And then he continuted:

Bah! This is what I get for not reading the question correctly and
in it's entireity -I'm just a potato with arms, legs and a head.
For setting up a file server, the best way to go for Windows is to
setup the Samba system or go NFS. You can find more information about SAMBA (the software package)


Nfs resources can be had at


O'Rielly's _Managing NFs and NIS_ by Stern is also an excellent
Guide. I can't think of any Samba books off hand, but they are definately
out there.
There is a good comparison of the two at


In case you are wondering while reading the above article, the
difference between UDP and TCP is that TCP tries to assure that packets
get to their destination, which takes longer while UDP does not. They are
referred to as connectionless and connection oriented protocols,
respectively. O'Rielly is a good publisher of mostly good books. If you are
serious about this home networking project, you can be quite skilled and
in high demand if your designs should follow that way. Armed with the
right literature, equipment and attitude, you should do well.

[Editor: I left your original article as well. More knowledge is always


zee180@lebhost.com.lb <zee180@lebhost.com.lb> says:

> pyromaniac <pyromanic@kmfms.com> sent in:
> what I don't really understand is what do I have to do for the linux
> machine to act as a server, how do i connect to it from one of the win
> machines, and what setup do i have to do in linux ?

There's a great tutorial dealing with IP masquerading here :



It's a step-by-step guide to configuring a server using Linux.


[Editor: There's also the IP Masquerading minihowto. Together, you should be


Fatal Error <lazerus001@juno.com> begs:

Maybe you can help me. I'm looking for a free distro of linux that'll run on
my PS/2 77i. It has MCA bus, 24 megs RAM, 2 gig HD, and a 486 DX/4 133mhz AMD CPU. I was hoping to breath some life into my comp before I result in getting a new one. Can you help me out?

[Editor: Anything. www.linux.org]



FREDIE MEZUI <mezuif@usa.net> asks:

Hi Mike,
Happy new year and many greetings for the new millennium.

I want to make you note just one thing concerning the teaching of the
Unix/Linux file system.

they tell the Dummie how to make:
boot disk
root disk
select what to install( Problems are begining here because as it is a new
thing for a generical dummie, he can not know what is essential for the
system, and after the installation where those $%&/£"£ files had been

To the poor dummie( for example ME..), they tell how to set up Xwindows,
how to set up the root password, but they do not teach you how the file system
is organized. i know that the Unix file system is fully customizable so it
could change from user to user or from a corporate to another one, but
for example what is the difference between /usr/bin and s/bin... nobody
tells you where to find the thing.

Another example, they tell to the dummie how to set up the DNS, so they
throw you to a file on the path /somtehing/another_thing/file. but what about the TSR called daemons and where to find them and what is there purpose. You could do it by following the instructions, wich are sometimes lightly buggy but working.
When it works but you remain with a missing segment in "you knowledge
to summarize, What i need is:
in Winodws systems , the file system is mainly on
C:\ C:\windows\system C:\windows\system32 and C:\windows...
it easy but with the unix things are quite differents.

So my question is : are there books or web site that can teach you the
structured of the unix file system and how to navigate on it ?

Probably you have already explained it in your digest, but i do hope you
gonna answer to me or better to al the Dummies like me. :-)))

thanks you very much.
Fredie M
Note: The english is not me native idiome so i could have made some mistake

[Editor: Flattery never hurts :). Seriously, as far as file systems go, there are two main organizations... depending on the variety of *nix, it'll vary. For the life of me, I never remember which are which. I do remember seeing a good book on the difference between System V and the other one (whatever it's called :) ). Do a web search, see what you can find. As far as bin vs. sbin... sbin is for system binaries, bin is for regular. A couple good commands to run a "man" on... which, find, where.]


Jacob <jratkiew@cs.iusb.edu> wrote:

I actively use tcsh. The shell prompt is configurable; look up prompt in the
tcsh man page for the full list of options (quite long). (If you don't have
the man pages, surf to http://linux.com.hk/man/)

For a usage example, here's my configuration:

# this is in the .tcshrc file.
set prompt="%B%m%b %~ %% "

this gives me the hostname in bold, followed by my current working
directory, followed by a % and a space. Another prompt I use is:

set prompt="[ %B%m%b %c2 ]# "


which is similar to the above except that it shows only the last two terms
of the current working directory.




Cyanide84@aol.com <Cyanide84@aol.com>

>matt morgan <neptune2002@hotmail.com> wrote:
>I would like to know whether a tcsh prompt is configurable
>and how to configure it
>I have been told that a "set prompt=" in .cshrc might work
>but I am having no luck finding someone that actively uses tcsh
>also there are no man pages for tcsh on my computer

This is easy to do. Under my tcsh, I put my prompt settings under ".login".
Just fire up vi, or your fav. editor and open .login, at the end type in
"set prompt = "(minus the quotes) and put the variables in after that. Easy as
pie, n'est pas?

"Just because your paranoid, doesn't mean they're not after you!"

[Editor: "Even paranoids have enemies" (Henry Kissenger)]

Martijn Linssen <email@withheld.com> asks

Hi Happy Hacker,

I've read all your documentation, and enjoyed it! Thank you for sharing
your knowledge, I've learned a lot.
I encountered a UNIX (HP-UX) funnybunny when I had changed my password
the other day (I have experience with mainframes (ICL-Open VME),
midiframes (AS/400 4.2), and lots of OS (DOS x.x, Win 95, 98, NT, OS/2,
but this one startled me): I use the "same" password for every system
I'm working on, since this is a matter of weeks or months, and passwd'd
the password on UNIX, as I'm used to do.

I couldn't log on the next day, untill I tried my usual routine, which
Apparently UNIX counts the TAB as being part of your password, although
it doesn't show anything due to the -echo option, but anyhow: just
change your password to "password" + TAB, and I think that it will be
really hard to crack it ;-}

FYI: this is my first real UNIX, so it takes some time getting
acquainted to.
I'd like to be subscribed to your Happy Hacker List, but couldn't find
it. Does it still exist?

Kind regards,

Martijn Linssen

[Editor: Nifty idea. Has anyone tried this... does it work on different
systems? BTW, I suppose you don't want to hear the lecture on using the same
password... the HH Digest still exists (you're reading it now :) ) I
presume, because of the antispam instructions on your email addr, you didn't
want it posted, correct?]


John Kurt <enrique_1970@yahoo.com> asks


First of all, thank you very much for all the
information you make available, this has saved me from
being bored at night.

I have a question and I have been unable to find the
answer to this:

Several weeks ago I was in a chat room spending some
time with some hackers and it seems that someone
didn't like my presence there, somehow I was "nuked".
I didn't understand how they did it, but I came back
to the same chat room, this second time one of them
displayed my IP number on screen, I made a netstat -a,
but all I could see was port 1025 and the chat server
port 8002 connecting stablished.

How could this hacker find out my IP ?, How can I
protect myself in the future ?, I was using Netscape
Comunicator 4.6.

Please, any info or advice will be greatly

[Editor: Hmmm. Sure this is a unix question? I think nuking is a topic
that's been beaten to death already... basically, it's a Denial of Service
attack. If you're not familiar with the idea... imagine giving someone a
nervous breakdown by calling their housing non-stop... on all 10 of their
lines... for a week... with a shrill ringing sound played when they answer.
Oh, and they need to let legit calls get through. That's a DOS. if you were
on IRC, your IP addr is easy to find (/whois + /who). If you were on a java
based chat... it'd depend. Basically... there are mean people out there. If
you're running windows <insert flame here>, and download NukeNabber. For
Unix... you should be safe.]


Adam asks:

KingLou says: A little linux help...
...for a confused schumck like myself. Well, let me start off by saying
that your page has gotten me very interested in obtaining some form of
linux. Even though have yet to retain any concrete knowledge of this so
called "hacking" that you speak of, I am interested nonetheless. Since I
can't really run around looking for places to purchase linux (because I must
do everything from the privacy of the dark pit of mystery that is my room),
I did some research into the different linux distributions that are
available for free download on the internet. I came up with two
possibilities that seemed promising, and I wondered what kind, if any,
knowledge you had of these particular distributions. The ones that caught
my eye were armed linux and winlinux 2000. Both claim to be compatible with
windows 95, which is exactly what I'm looking for because I don't want a
whole new operating system taking over where windows used to be, because I
don't want to be throwing up too many red flags for my snoopy parents to
see. I was wondering if you knew anything about these programs and if my
understanding of them is accurate (my understanding being that I can use
windows to run these applications rather than having them take over as my
main operating system)? Any help and/or suggestions you could offer would
be greatly appreciated.

[Editor: I knew this for dummies/idiots/schmuck (the m is before the u)
thing was going too far... anyway... I know nothing about either app. Hey,
you can always convince your parents to give you money to buy a 486... or
get a job :) ]


Eric Korman <eok86@mail.com> wonders:

Hi, I'm a newbie at hacking, I would like to become a white hat hacker. I
have read numerous webpages, like yours, that tell all the wannabees to get
Linux. So, I did what it said and bought Linux, had trouble installing it,
but installed and was able to access the internet. But I am not able to
understand why Linux is a better operating system for hakcing than Windows.
To me, the internet veiwing seems the same, and that I could do all that on
Windows with IE and telnet. If you could please reply to this e-mail, it
would be highly apreciated.

[Editor: Hmm. I don't think hacking is about viewing the internet. That's
called "viewing the internet". I guess it depends what you mean by
hacking... let's just say that Linux gives the low-level access that windows
doesn't. Plus there's more code for Linux. That's basically it in a


This is a list devoted to *legal* hacking! If anyone plans to use any
information in this Digest or at our Web site to commit crime, go away! We
like to put computer criminals behind bars where they belong!


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