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how to check the variable values is blank

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# 1  
Old 12-06-2008
Bug how to check the variable values is blank
HI ,
I have to check the values of variable is blank or not.
exm :
###test
test1


var=`cate filename | head -1 | cut -c1-3`
I need to check the first three character of 1st line . if it is blank .then exit or we need to process .

Thanks in advance .
# 2  
Old 12-06-2008
Something like the following should work
Code:
if [[ -z $var ]]
then
      echo "Empty var"
      exit 1
fi

# 3  
Old 12-06-2008
unrelated but I would suggest changing the

Code:
var=`cate filename | head -1 | cut -c1-3`

line to

Code:
var=`head -1 filename| cut -c1-3`

There is no reason to read the entire file when you only need the first line.
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