A small script to take a larger text based file and break it down to several smaller files

split.sh

#!/usr/bin/env bash

# A small script to take a larger text based file and break it down to several smaller files
# of 500 lines each for easier processing, keeping the headings at the top of each file

FILENAME=${1}

if [ -z ${FILENAME} ]; then
  echo "Please provide a filename, for example: bash split.sh /path/to/data.csv";
else

  CLEAN_FILENAME="${FILENAME/-*\./.}"
  CLEAN_FILENAME=${CLEAN_FILENAME%.*}

  tail -n +2 ${FILENAME} | split -a 5 -d -l 500 - ${CLEAN_FILENAME}_

  for file in ${CLEAN_FILENAME}_*
  do
      head -n 1 ${FILENAME} > tmp_file
      cat ${file} >> tmp_file
      mv -f tmp_file ${file}.csv
      rm ${file}
  done

  echo ${CLEAN_FILENAME}
fi