multithreaded split file with sed

concurrent.sh

#!/bin/bash

worker=8
args=("$@")
file=${args[0]}
lines=$(wc -l $file | awk -F ' ' '{print $1}')
linesPerWorker=$(expr $lines / $worker)
start=1
mkdir -p tmp

waitforjobs() {
  while test $(jobs -p | wc -w) -ge "$1"; do wait -n; done
}

splitfile(){
  i=${i} file=${2} start=${3} end=${4}
  filename=$(basename $file)
  tmpfile=$(mktemp -p tmp)
  echo "--- work: ${tmpfile} $start:$end"   #echo "${i} $file ${start} ${end} ${file} "
  sed -n "${start},${end} p;${end}q" $file > "${tmpfile}"
  ./bulk2raw.lua ${tmpfile} ${file}
  rm -f ${tmpfile}
}

echo ""
echo "--- BSPLIT ${file} into ${worker} chunks"

for i in $(seq 1 1 $worker); do
  end=$(($start + $linesPerWorker))
  splitfile ${i} $file ${start} ${end} &
  start=$(($start + $linesPerWorker+1)) # incr for next run
done

waitforjobs 1

echo "--- ALL CHUNKS ${worker} PROCESSED for: ${file} ...deleting"
echo ""
rm -f ${file}