シェルスクリプトのテンプレート

template.sh

#!/bin/bash
#
# {SUMMARY}
#
# USAGE
#   sh {SCRIPT_FILENAME} -h
#
# REMARKS
#   https://www.m3tech.blog/entry/2018/08/21/bash-scripting
#

# bashのスイッチ
set -euC

# 外部スクリプトのsource
#source ./setting.inc

# グローバル定数
readonly SCRIPT_DIR=$(cd $(dirname $0); pwd)

# グローバル変数
INPUT_FILE=
OUTPUT_FILE=
FLAG_A=0

# 後処理
function cleanup() {
  # do something
  true
}
trap cleanup EXIT

#
# 関数定義
#

function usage() {
  cat <<EOS >&2
Usage: sh $(basename "$0") [OPTIONS] <input_file>

  DESCRIPTION
    {DESCRIPTION}

  OPTIONS
    -o output_file  Output in the file
    -a              Do something
    -h              Show this help
    -v              Execute with debug mode

  EXAMPLE
    Show content of \`README.md\` in stdout

      $ sh $(basename "$0") README.md

    Show this help

      $ sh $(basename "$0") -h

EOS
}

function show_content() {
  local input_file="$1"
  local output_file="$2"
  local flag_a="$3"

  if [[ "$output_file" != "" ]] && [[ $flag_a -eq 1 ]]; then
    cat <<EOS
    cat "$input_file |>> $output_file"
EOS
  elif [[ "$output_file" != "" ]]; then
    cat <<EOS
    cat "$input_file |> $output_file"
EOS
  else
    cat <<EOS
    cat "$input_file"
EOS
  fi
}


#
# 引数parse処理
#
function parse_args() {
  while getopts "o:vah" opt; do
    case $opt in
      v) set -x ;;
      o) OUTPUT_FILE=$OPTARG ;;
      a) FLAG_A=1 ;;
      h) usage; exit 0 ;;
      *) usage; exit 1 ;;
    esac
  done

  shift $((OPTIND - 1))

  INPUT_FILE=${1:-}
  if [[ "$INPUT_FILE" == "" ]]; then
    usage
    exit 1
  fi
}


#
# メイン処理
#
function main() {
  local input_file="$1"
  local output_file="$2"
  local flag_a="$3"

  show_content "$input_file" "$output_file" "$flag_a"
}
# エントリー処理
if [[ "${BASH_SOURCE[0]}" == "${0}" ]]; then
  parse_args "$@"
  main "$INPUT_FILE" "$OUTPUT_FILE" "$FLAG_A"
fi