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This article was posted to the Usenet group alt.hackers in 1995; any technical information is probably outdated.

Re: Tell me

Article: 7659 of alt.hackers
From: (Jeremy Dilatush)
Newsgroups: alt.hackers
Subject: Re: Tell me
Date: 14 Apr 1995 20:38:31 GMT
Organization: (none)
Lines: 54
Approved: If you can read this...yes.
Message-ID: 3mmmg7$
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Status: RO

>       Exactly, I doubt it.  Someone let me know if you read this.

I didn't read the message quoted above, so I won't.

If I'm interpreting things correctly, your post is a 'first try'.  Well, you
succeeded in posting.  And if anybody's reading this, so did I.  :')

One thing I'm afraid your forgot about posting here is your

ObHack (April-Fools type)
        This year was great for AFJ's ... I participated in three and
witnessed two.  One I engineered myself:
        Our CS department keeps a cluster of Sun SPARC machines running
SunOS Unix -- nice systems.
        Anyway, from about 9:30pm on March 31 (I kinda jumped the gun)
to 11:00pm on April 1, everyone who sat down at the machines and logged
in (remote logins are not involved here) got a message to their terminal.
The message started in their console window (an 'xterm') with a sequence
of beeps (separated by fraction-of-a-second pauses so they wouldn't
blend together).  Then that window cleared, a black border was drawn
around it, and text started appearing, with boldface, beeps, pauses,
etc.  The gist of the text was this:
        "Yo bub -- this is the computer.  I'm tired of compiling those CS
assignments you think so important, I'm bored of those WWW pages you
think so interesting; I think I'll go out and get a beer -- April Fools!"

        As an AFJ it wasn't too great (Saturday is a bad day for
that sort of hack, damn it!) but I think it's a cool ObHack 'cuz:
        - I did it all under my own uid.
        - I used the fact that /dev/console is world-writable
on these machines -- there's good reasons for it to be, in fact, but
nobody ever _thinks_ of it being writable.
        - I used the VT100 control sequences (xterm emulates a VT102)
Nobody ever thinks about them being there.  People are
too used to GUIs to think about _how_ windows, etc, get put up within
their text screens.  So I just looked at TERMCAP (using the man page
for translation) did some experimenting, and tailored my message with
lots of cheap-but-wizardly-looking text formatting.

The thing was implemented in two parts, a C program that did the actual
message output.  And a Bourne shell script that, every 120 seconds,
used 'finger' to find out who was logged in, used 'grep' to find out
who was actually at the console, used some hack I don't clearly remember
to figure out who was _new_, shelled to the machine and ran the message
program.  (Sorry about the run-on sentence)

I know, I could have done that last part in Perl in seconds but I haven't
gotten around to learning it yet...

OK so you had to be there.  (preferably not expecting it and having no
idea how anybody could do it w/out root access)

And Mark -- I'm looking forward to reading your ObHack.

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