Shell script, saving the command value to a variable

I am trying to print the value of VARI in the same line followed by a comma, so that i can have a csv file of these values, but i m not able to save the value of VARI =开发者_如何学JAVA 'cat filename | head -1 | cut -d, -f${i}'

i=0
while (( i<130)) ;
do
  if [[ $i -eq 1 ||  $i -eq 9 || $i -eq 12 || $i -eq 23 || $i -eq 25 || $i -eq 29 ]]
  then
    VARI = 'cat filename | head -1 | cut -d, -f${i}'
    echo  "$VARI ,"   
  fi
  let i=$i+1;
done

output expected is

4,abc,5,8,xyz,9

Please let me know what i am doing wrong, thanks!

use backticks (or $() – can be nested), not single quotes:

VARI=`cat filename | head -1 | cut -d, -f${i}` # or:
VARI=$(cat filename | head -1 | cut -d, -f${i})