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From: chas@ihuxe.UUCP (Charles Lambert)
Newsgroups: net.unix
Subject: Test for login shell
Message-ID: <1034@ihuxe.UUCP>
Date: Tue, 22-Jan-85 18:11:00 EST
Article-I.D.: ihuxe.1034
Posted: Tue Jan 22 18:11:00 1985
Date-Received: Thu, 24-Jan-85 05:43:15 EST
Organization: AT&T Bell Labs, Naperville, IL
Lines: 11

Can anyone suggest a reliable test to determine whether
a shell script is executing in the highest-level instance
of the shell (by "." invocation) or in a child shell
(by normal invocation).

I need to write a script which will "exec" a program if
it is NOT executing at the log-in level (because the session
would disappear on termination of the command).

Mail answers to me, I'll post the best solutions later.