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Script to check for null values in a column


 
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# 1  
Old 09-03-2013
Script to check for null values in a column

Hi Guys,

I am new to shell script.I need your help to write a shell script.
I have a csv file which has 13 columns separated by ,
I have written below script to fetch required 5 columns.
Code:
 awk -F, '(NR==1){h3=$3;h4=$4;h8=$8;h9=$9;h13=$13;next}(NF>1) \
{print h3":"$3"\n"h4":"$4"\n"h8":"$8"\n"h9":"$9"\n"h13":"$13}' $IFILE > $OFILE

Now i want to include condition in above script to check if column 13 is null/empty and if yes print ouptput "error in file".
# 2  
Old 09-03-2013
Code:
awk -F, '! $13 { print "Error in file">"/dev/null"; exit }
{print h3":"$3"\n"h4":"$4"\n"h8":"$8"\n"h9":"$9"\n"h13":"$13}' $IFILE > $OFILE

# 3  
Old 09-03-2013
Thanks for the reply.
I am tried by using the below if loop after my print stattement but not working..any idea why.
Code:
if [ $h13 == "" ]; then
echo "error in file format column " > $OFILE

also tried
Code:
if [ $h13 = "" ]; then
echo "error in file format column " > $OFILE


Last edited by vbe; 09-03-2013 at 01:56 PM..
# 4  
Old 09-03-2013
Because awk is awk, shell is shell, and they don't use each others' variables.

What are you trying to do?
# 5  
Old 09-03-2013
Try this:
Code:
if ! awk -F, '! $13 { print "Error in file">"/dev/null"; exit 1 }
        {print h3":"$3"\n"h4":"$4"\n"h8":"$8"\n"h9":"$9"\n"h13":"$13}' $IFILE > $OFILE
then
        echo "error"
fi

# 6  
Old 09-04-2013
Should be $13=="" not ! $13; the latter treats a 0 like a "".
If you want to include the error in the output file, you can do that in awk
Code:
awk -F, '
($13=="") {print "Error in file"; exit 1}
(NR==1) {h3=$3;h4=$4;h8=$8;h9=$9;h13=$13; next}
{print h3":"$3"\n"h4":"$4"\n"h8":"$8"\n"h9":"$9"\n"h13":"$13}
' $IFILE > $OFILE

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