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Shell Programming and Scripting

Meaning of -Z operator

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# 1  
Old 07-26-2012
Meaning of -Z operator
Hi

i am not able to understand the use of -Z in below script.

Code:
RESPONSE=
while [ -z "$RESPONSE" ] ;
do
echo "Enter the name of a directory where your files are located:\c "
read RESPONSE
if [ ! -d "$RESPONSE" ] ; then
echo "ERROR: Please enter a directory pathname."
RESPONSE=
fi

done
# 2  
Old 07-26-2012
-z will check whether the string is null or not. In your case RESPONSE doent contain any value so -z "$RESPONSE" return true and enter in to while loop.
# 3  
Old 07-26-2012
[ .... ] is just short for test .... See the manpage for "test" (which is a Unix command and resides usually in /usr/bin/test) for details about the various options for "test".

I hope this helps.

bakunin
# 4  
Old 07-26-2012
Advanced Bash Scripting Guide -- Reference Cards is a really nice reference for flags you don't know. Look under 'test operators - files'. A few of these may be BASH-specific but the vast majority work in any shell.
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