split csv into n files with each file containing content as well as csv header

cut.sh

inputfile=$1

filename="${inputfile%.*}"

line_count=$(wc -l < $1)

row_count=$((${line_count} - 1))

movement=$(($row_count/$2))

i=0
j=1

while [ $j -lt $row_count ]
do
    # echo $(($j + 1))
    # echo $(($j + $movement))
    t="${filename}-${i}.csv"
    touch $t
    head -n 1 $1 > $t
    cat $1 |  sed -n "$(($j + 1)),$(($j + $movement ))p" >> $t
    j=$[$j + movement]
    i=$[$i+1]
done