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Re: When double quote is considered when not?
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From: |
Mart Frauenlob |
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Subject: |
Re: When double quote is considered when not? |
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Date: |
Wed, 30 Mar 2011 14:09:46 +0200 |
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User-agent: |
Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2.15) Gecko/20110303 Lightning/1.0b2 Thunderbird/3.1.9 |
On 30.03.2011 12:13, ali hagigat wrote:
The following scripts were run for /bin/bash, version 4.0.33, and then
comes their outputs. In the second example seems to have a warning:
"binary operator expected". Why the error is generated? and why there
is no error for the first example?
----------------------------------
var1="word1 word2"
echo $var1
if (test -z "\"$var1\"") then
why run the test in a subshell?
is there any reason for the second quote pair?
echo "first"
else
echo second
fi
word1 word2
second
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var1="word1 word2"
echo $var1
if (test -z ""$var1"") then
"" expands to nothing, as nothing in between opening and closing quote.
$var1 (now unqoted) expands to 'word1 word2', so the test command sees
'word2' while it expects another operator.
echo "first"
else
echo second
fi
word1 word2
./ss1: line 3: test: word1: binary operator expected
second
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