bashのgetoptsの使い方

getopts.bash

#!/bin/bash

usage() {
  cat <<EOF
usage: $0 [options] FILE...

  -h    show this help
  -n    specify number
EOF
}

while getopts "hn:" opt; do
  case $opt in
    h)
      usage
      exit 0
      ;;
    n)
      NUM="$OPTARG"
      ;;
    *)
      usage 1>&2
      exit 1
      ;;
  esac
done
shift $((OPTIND-1))

if [ $# -eq 0 ]; then
  usage 1>&2
  exit 1
fi

echo num: $NUM

for f in "$@"; do
  if [ -e "$f" ]; then
    echo exists $f
  else
    echo not exists $f
  fi
done