Path: utzoo!attcan!utgpu!news-server.csri.toronto.edu!clyde.concordia.ca!uunet!tut.cis.ohio-state.edu!husc6!cmcl2!kramden.acf.nyu.edu!brnstnd
From: brnstnd@kramden.acf.nyu.edu (Dan Bernstein)
Newsgroups: comp.unix.questions
Subject: Re: login shell suspend
Message-ID: <2824:Aug1914:08:2790@kramden.acf.nyu.edu>
Date: 19 Aug 90 14:08:27 GMT
References: <498@llnl.LLNL.GOV>
Sender: brnstnd@kramden.acf.nyu.edu (Dan Bernstein)
Organization: IR
Lines: 23
X-Advertisement-Warning: On

In article <498@llnl.LLNL.GOV> rjshaw@ramius.llnl.gov () writes:
> Who knows the history behind "Can't suspend a login shell (yet)."

When you suspend a shell, you're dumped back into the shell above it.
The ``logical'' extension of this behavior to a network is what rlogin
does when you type ~^Z at the beginning of a line. The connection is
still there, but rlogin ignores it.

The intuitive---and much more useful---extension of this behavior is
what my pty program does upon a typed or accidental disconnect. The
connection disappears entirely, but the tty session sticks around,
blissfully unaware of anything going on. Later you can reconnect, from a
different terminal, a different network, even piping input and output
through other programs. You don't get screwed by a dying terminal or a
fuzzy connection: just hang up, move to the next terminal, and
reconnect.

pty has only been widely available this summer; the shell is much older.
Whoever stuck ``Can't suspend a login shell (yet)'' into the shell was
dreaming of features only available in dreams, Steve Bellovin's proposed
session manager, and VMS. Now those features are here, for BSD at least.

---Dan