Shell 获取指定日期的前N个季度的起止日期

date_before_seasons.sh

#!/usr/bin/env bash
:<<describle
  desc: 获取指定日期的前N个季度的日期
  author: Answer.AI.L
  datetime: 2019-09-11 16:17:39
  params:   report_dt 日期, 格式:yyyy-mm-dd
            reasons 返回N个前移的季度
describle
# set -x

# 日期, 默认当前日期, 格式: yyyy-mm-dd
[ $1 ] && date=$1 || date=`date +%Y-%m-%d`
# 返回N个前移的季度
[ $2 ] && rltCnt=$2 || rltCnt=4
# 返回N个季度信息的数组
rtnSeasons=()

:<<comments
  获取指定date的前rltCnt个季度信息
  @param date
  @param rltCnt
comments
function dateBeforSeasons(){
  # 注意该字段为全局变量, 每次使用需要清空数组
  unset rtnSeasons
  local date=$1
  local rltCnt=$2
  echo "calculate date: "${date}
  # 把日期中的-字符全部替换为空格
  date=${date//-/}
  # 从第4位开始截取date字符串并对其进行转为数字
  local dt=`expr ${date:4} + 0`
  local year=${date:0:4}
  local ruleArr=(101'<='${dt}'&'${dt}'<='301 401'<='${dt}'&'${dt}'<='630 701'<='${dt}'&'${dt}'<='930 1001'<='${dt}'&'${dt}'<='1231)
  # 季节数组, 01010331 -> 第一季节
  local seasonArr=('01010331' '04010630' '07010930' '10011231')
  local nowSeason=0

  for (( i=0; i<${#ruleArr[@]}; i++ ))
  do
    # 判断当前月份所属的季度
    if [ $[${ruleArr[i]}] -eq 1 ];then
      nowSeason=${i};
      break
    fi
  done

  #echo ${date}"属于第"${nowSeason}"季度"
  # 取当前季度的上一个季度
  let nowSeason--

  for (( i=0; i<${rltCnt}; i++ ))
  do
    # 如果当前季度小于0(0为第一季度), 则年份前推一年
    if [ ${nowSeason} -lt 0 ]; then
      let year--
      let nowSeason+=4
    fi
    local index=$((nowSeason%4))
    local prevmd=${seasonArr[index]:0:4}
    local nextmd=${seasonArr[index]:4}
    local prev_month=${prevmd:0:2}
    local prev_day=${prevmd:2}
    local next_month=${nextmd:0:2}
    local next_day=${nextmd:2}
    rtnSeasons[i]=${year}"-"${prev_month}"-"${prev_day}"~"${year}"-"${next_month}"-"${next_day}
    let nowSeason--
  done

  echo "date: "$1", cnt: "${rltCnt}" -> rtnSeasons: "${rtnSeasons[@]}
}


dateBeforSeasons 2019-09-11 8
echo "rlt: "${rtnSeasons[@]}

:<<test 测试
dateBeforSeasons ${date} ${rltCnt}
echo "rtnSeasons length: "${#rtnSeasons[*]}
for v in ${rtnSeasons[@]}
do
  echo ${v}
done

dateBeforSeasons 2019-09-11 8
echo "rlt: "${rtnSeasons[@]}
test
# set +x

获取 2019-09-11的前8个季度的起止日期

dateBeforSeasons 2019-09-11 8

2019-04-01~2019-06-30 2019-01-01~2019-03-31 2018-10-01~2018-12-31 2018-07-01~2018-09-30 
2018-04-01~2018-06-30 2018-01-01~2018-03-31 2017-10-01~2017-12-31 2017-07-01~2017-09-30