BASH date picker

Sometimes I need users to pick a date from within a bash shell but I need the format to be correct. This little script lets users pick a date and it will output in whatever format the script needs.

Users can use the arrow keys to move the date on the calendar and press enter to select the date.

#!/bin/bash

DONE=0
DATE=$(date +%F)
YEAR="$(echo $DATE | cut -b1-4)"
MONTH="$(echo $DATE | cut -b6-7)"
DAY="$(echo $DATE | cut -b9-10 | sed -e 's/^0/ /')"
while [ $DONE -eq 0 ]; do
 clear
 cal -h ${MONTH} ${YEAR} | GREP_COLOR='47;30' grep "$DAY" -wC6 --color=always
 read -rsn1 KEY
 [[ $KEY == $'\x1b' ]] && { 
  read -rsn1 -t 0.1 DC
  read -rsn1 -t 0.1 KP
  case $KP in
   "A") DATE=$(date +%F -d "$DATE 7 day ago");;
   "B") DATE=$(date +%F -d "$DATE 7 day");;
   "C") DATE=$(date +%F -d "$DATE 1 day");;
   "D") DATE=$(date +%F -d "$DATE 1 day ago");;
  esac
 } || { 
  DONE=1
 }
 
 YEAR="$(echo $DATE | cut -b1-4)"
 MONTH="$(echo $DATE | cut -b6-7)"
 DAY="$(echo $DATE | cut -b9-10 | sed -e 's/^0/ /')"
done
echo $DATE

# To change the output format use the date command like these examples do
# date +%d/%m/%Y -d "$DATE"
# date -d "$DATE"