split-csv

#!/usr/bin/env bash

file=$1
n=$2

if [[ $# -lt 2 ]]; then
cat <<- EOD
Usage: $0 <path> <number_of_files>
EOD
fi

split_csv() {
    header=$(head -1 $1)
    dir=$(dirname $1)
    base=$(basename $1 ".csv")

    mkdir -p "$base"
    lines=$(wc -l $1 | xargs echo | cut -d ' ' -f1)
    chunk=$(node -e "console.log(Math.ceil($lines / $n))")
    tail -n +2 $1 | gsplit -l $chunk -d - "$base/$base."
    for i in $base/$base*; do
      [[ $i = $1 ]] && continue
      echo "$header" > $i.csv
      cat $i >> $i.csv
      rm "$i"
    done
}

split_csv $1 $2