Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!zaphod.mps.ohio-state.edu!rpi!uwm.edu!psuvax1!hsdndev!cmcl2!kramden.acf.nyu.edu!brnstnd
From: brnstnd@kramden.acf.nyu.edu (Dan Bernstein)
Newsgroups: comp.arch
Subject: Re: Ignorance speaks loudest (was:Computers for users not programmers)
Message-ID: <2983:Feb1213:30:1791@kramden.acf.nyu.edu>
Date: 12 Feb 91 13:30:17 GMT
References: <13252@lanl.gov> <1652@hpwala.wal.hp.com> <43615@cos.com>
Organization: IR
Lines: 53

In article <43615@cos.com> fetter@cos.UUCP (Bob Fetter) writes:
  [ reconnect under UNIX? ]

acf3% telnet kramden
Trying...
Connected to KRAMDEN.ACF.NYU.EDU.
Escape character is '^]'.


SunOS UNIX (kramden)

login: brnstnd
Password:
  [ random login notices, deleted from this script ]
session p1 sigler 2768 master 1380 slave 1381
session p1 disconnected
Reconnect to session (return to ignore): p1
reconnect: p1 set, will reconnect after p3 drops
pty: reconnecting to /dev/ttyp1
pty: successfully reconnected to /dev/ttyp1

kramden% jobs
[1]  + Stopped              rn
kramden%
  [ now I type ^] and disconnect ]
telnet> quit
Connection closed.

The modem connection conveniently died while I was typing this article,
so I dialed back in, logged into a different machine, made the above
typescript, and then reconnected again to finish typing.

Here's what my .login does to perform these dastardly deeds:

sesslist
sesslist | grep -s disconnected \
  && ( echo -n 'Reconnect to session (return to ignore): '; \
       set reconnect="$<"; \
       if ( a"$reconnect"b != ab ) exec sess reconnect "$reconnect"; \
     )

The pty package (which includes sess, reconnect, etc.) should work
without too much angst on any BSD-based system; I'm willing to port it
to any machine I can get my hands on. I just completed draft 9 of
``The Design, Implementation, and Use of a Pseudo-Terminal Manager,''
which describes the pty interface (and lots of gory BSD tty bugs) in
detail, and illustrates some neat tricks (like suddenly deciding to
record a talk session already in progress) that you simply can't do
under most systems with reconnect facilities. The package is available
via anonymous ftp from 128.122.128.22; the paper is available from me
directly.

---Dan