From: jesse@mail.CS.Uni-Magdeburg.De (Roland Jesse)
To: zsh-users@sunsite.auc.dk
Subject: Parameter expansion
Date: Mon, 17 May 1999 11:39:18 +0200 (METDST) [thread overview]
Message-ID: <14143.58310.693584.42423@busch.cs.uni-magdeburg.de> (raw)
The zsh manual says regarding to parameter expansion:
${+name}
If name is the name of a set parameter `1' is substituted, otherwise `0' is
substituted.
But why do I do get the following than?
% if [ ! ${+BLURB} ]; then
then> echo "BLURB not set"
then> else
else> echo "BLURB set"
else> fi
BLURB set
%
I was expecting the opposite. Curiously:
% export BLURB=foo
% if [ ! ${+BLURB} ]; then
echo "BLURB not set"
else
echo "BLURB set"
fi
BLURB set
%
Maybe the question should be: How do you check whether or not an
environment variable is set?
Comments are appreciated.
Roland
next reply other threads:[~1999-05-17 9:40 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
1999-05-17 9:39 Roland Jesse [this message]
1999-05-17 9:23 ` Peter Stephenson
-- strict thread matches above, loose matches on Subject: below --
2017-08-13 22:58 Parameter Expansion Clint Priest
2017-08-13 23:51 ` Bart Schaefer
2017-08-14 0:07 ` Bart Schaefer
2017-08-14 1:16 ` Clint Priest
1999-03-31 14:35 Parameter expansion Mircea Damian
1999-03-31 14:54 ` Geoff Wing
1999-03-31 15:04 ` Mircea Damian
1999-03-31 15:51 ` Bart Schaefer
1999-04-01 6:20 ` Rob Hooft
1999-04-01 7:30 ` Geoff Wing
1999-04-01 7:33 ` Bart Schaefer
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