Shell Programming and Scripting

echo "Enter the number of records: "
  read n
  rm data.txt
  echo "Name" "Roll no." "Marks 1" "Marks 2" "Marks" >> data.txt
  for((i=0;i<n;i++)) #here is the error
  do

    echo "Enter the name: "
    read name
    echo "Enter the roll number: "
                                                              1,1           Top
        read rollno
    echo "Enter the marks in subject 1: "
    read m1
    echo "Enter the marks in subject 2: "
    read m2
    echo "Enter the marks in subject 3: "
    read m3
    echo $name $rollno $m1 $m2 $m3 >> data.txt
  done

for (( i = 0; i < n; i++ ))

 for (( i = 0; i < n; i++ ))

for i in {1..$n}