login shell suspend

[Dan Bernstein]

In article <498 at llnl.LLNL.GOV> rjshaw at 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