Parse date value supplied to a bash script-CodePudding

I'd like to be able to pass dates to a script in the form of yyyy-mm, mm/yyyy, yyyy-mm-dd, and mm/dd/yy.

For example:

$ ./parse.sh 2021-03 2021-03-14 3/14/19 11/2019
year: 2021 / month: 03 / day: 
year: 2021 / month: 03 / day: 14
year: 2019 / month: 03 / day: 14
year: 2019 / month: 11 / day:

This script works for values that have year, month, and day, but not just for year and month:

#!/usr/bin/env bash

for arg in "$@"
do
    # echo "parsing $arg..."

    read -r y m d <<< "$(date ' %Y %m %d' -d "$arg")"
    echo "year: $y / month: $m / day: $d"

done

Example:

$ ./parse.sh 2021-03 2021-03-14 3/14/19 11/2019
date: invalid date ‘2021-03’
year:  / month:  / day: 
year: 2021 / month: 03 / day: 14
year: 2019 / month: 03 / day: 14
date: invalid date ‘11/2019’
year:  / month:  / day:

Any suggestions on how to handle the month/year combination correctly?

CodePudding user response：

#!/bin/bash
for arg
do
    case $arg in
    *-*  ) IFS='-' read -r year month day ;;
    */*/*) IFS='/' read -r month day year ;;
    */*  ) IFS='/' read -r month year day ;; # day is here for reset
    esac <<< "$arg"
    echo "year: $year / month: $month / day: $day"
done