Shell Programming and Scripting

echo "script running for the 1st time"
cp value_directory_present.txt /home/mysql_cnbc/value_directory_past.txt
rm -f test6.txt value_directory_present.txt
else
y1=`awk '{print $1}' value_directory_past.txt`
z=`expr $y - $y1`
echo $z
if [ $z = 0 ];then
echo "rate is zero"
rm -f value_directory_present.txt test6.txt test7.txt
break
else
z1=`$z/$y1`
echo $z1
z2=`100 * $z1`

+ find . -type f -name value_directory_past.txt
+ var=./value_directory_past.txt
+ [ ./value_directory_past.txt == '' ]
+ awk '{print $1}' value_directory_past.txt
+ y1=23789264
+ expr 23789328 - 23789264
+ z=64
+ echo 64
64
+ [ 64 = 0 ]
+ 64/23789264

test4.sh: line 32: 64/23789264: not found

+ z1=''
+ echo