am I in background?

[Doug Gwyn <gwyn>]

> There's no way to tell if you were run in the background that works with all
> shells on all systems.  Besides, if you have job control you may have been
> in the background 10 minutes ago but may be in the foreground now.  If you
> need to know this, think harder about *why* you need to know this; you may
> find that you don't really need to know it, or that it isn't really want you
> need to know.

Yes, yes!  A plea to UNIX software developers:  Please remember
what UNIX is all about, and make your tools as generally useful
as possible.  For example: create a separate computation program
that is unaware of the details of its environment, and create a
separate driver program if you must for interactive use on brain-
damaged video terminals.  (No, ordinary video terminals are NOT
the nicest interactive interface.)  Indeed, it is easy enough to
provide an interactive shell script that prompts the user through
parameter specification and then invokes the real, general-purpose
program with the right arguments and plumbing; often that is quite
user-friendly enough.