#!/bin/bash

CMD="split -d -a 4"
_help() {
  split --help
  echo ""
  echo "My default switches for split utility"
  echo "$CMD -b 500M FILE FILE."
}
_helpexit() {
  _help
  exit
}

for (( i=1; i<=$#; i++ )); do 
  [[ ${!i} = "-h" ]] && _helpexit
  [[ ${!i} = "--help" ]] && _helpexit
done

args=( )
for (( i=1; i<=$#; i++ )); do 
  test -f "${!i}" && {
    file="${!i}"
    # file found, remove from arguments
    set -- "${@:1:i-1}" "${@:i+1}"
  }
  [[ "${!i}" = "-b" ]] && SIZE_SET=1
done

[[ "$SIZE_SET" -eq 1 ]] || {
  size="-b 500M"
}
test -f "$file" || { echo "No such file"; exit 1; }
set -x
pv "$file" | $CMD $size "$@" - "$file".