README for the script piep
==========================

This is the small script called piep. Wondering about
the name? Me too.

Installation is quite simple. Edit the config section
inside the script. Each option is described overthere.

Create a temporary directory. Do not just use /tmp,
because it has the sticky bit set which avoids deletion
of files, which one user does not own even if he has
write permissions to that file. But piep requires that
one user can delete a file, which was created previously
by another user.

example:
mkdir /var/tmp/.com
chgrp friend /var/tmp/.com
chmod 2770 /var/tmp/.com
ls -ld /var/tmp/.com
drwxrws---    2 scip  friend  4096 Jul 23 21:45 .com/

the sgid bit on this directory is required so that
your friends instance of piep can inherit group
settings.

mkfifo /var/tmp/.com/hier.00

that's the named pipe which is used during communication.
your friend needs read and write permissions on the pipe.


You will also need to install some perl-modules:

required:
  Digest::MD5
  Crypt::CBC
  Crypt::IDEA

optional:
  Crypt::DES
  Crypt::Blowfish

You will find them on your local CPAN mirror.
If you are not rewt on the host you are willing to install
piep, then use a directory under your home and copy the
modules by hand. In this special case you need to edit the
"use lib" line in the script, i.e.:
use lib "/home/scip/perl5";

You may also edit the first line of the script, it has to
point to suid-#!/usr/bin/perl, in most cases /usr/bin/sperl
or sperl5.005 or something like that. And you need to suid
the script:
chmod 4750 piep
This is required to make piep able to notify your partner if
you have quit piep using a signal, which is only allowed for
your own processes.



Usage is very straightforward: start it with
piep yourfirendsusername

It will ask you for a passphrase which will be
used to encrypt the conversation during this session.
Your friend is required to enter exactly the same phrase.

After your friend has also started piep, you can send/receive
messages. When you get a prompt like this:
<scip> 
then it is your turn to enter text, after entering you will
no more have a prompt until your firend has entered something.
And so on.

If one of the partners quits the session using CTRL-C the other
partner will be informed and his piep instance will also quit.



That's all about piep.



Use piep at your own risk. It is free software under the terms
of the well known GPL.



Author is <scip> member of the 49ers.
