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From: mouse@mcgill-vision.UUCP
Newsgroups: comp.unix.questions
Subject: Re: Environment variables
Message-ID: <879@mcgill-vision.UUCP>
Date: Sun, 6-Sep-87 02:30:10 EDT
Article-I.D.: mcgill-v.879
Posted: Sun Sep  6 02:30:10 1987
Date-Received: Sat, 19-Sep-87 05:39:59 EDT
References: <626@unmvax.unm.edu> <2876@phri.UUCP> <159@papaya.bbn.com>
Distribution: world
Organization: McGill University, Montreal
Lines: 34

In article <159@papaya.bbn.com>, rsalz@bbn.com (Richard Salz) writes:
> The problem is in distinguishing between "set var value" and
> "setenv var value" [...].

> Roy's idea of using printenv is probably better, but his method will
> probably cause quoting problems if you try to see if TERMCAP is set
> after using tset(1); this seems to do it:

> 	% if ( `printenv TERMCAP | wc -l` == 1 ) echo TERMCAP is set
> 	TERMCAP is set
> 	% if ( `printenv CAP | wc -l` == 1 ) echo CAP is set
> 	%

Or even just

if { printenv TERMCAP >& /dev/null } then
....
endif

WARNING if you try this:  The following does NOT work correctly.

if { printenv TERMCAP >& /dev/null } echo TERMCAP is set

This will print nothing regardless of whether TERMCAP is set or not,
becuase, believe it or not, the echo command gets its output redirected
by the redirection in the {}!  (Verified by changing /dev/null to
/tmp/foo - system is mtXinu 4.3+NFS, though the bug is present in a
local derivative of the 4.2 csh as well, and therefore is presumably
present in the 4.2 csh.)  The version using then and endif does not
suffer from the same problem.

					der Mouse

				(mouse@mcgill-vision.uucp)