Shell Programming and Scripting

#!/bin/bash 
# This script will ONLY accept two parameters in number format  
# according to "MM-DD" which is "XX-XX"  # To run this script: ./script.sh xx-xx xx-xx 
DATE1=$1 
DATE2=$2
 if [DATE1 is in correct format] && [DATE2 is in correct format]  
   then   
     echo "Correct format"   
     echo "DATE1 = $DATE1"   
     echo "DATE2 = $DATE2"  
   else   
     echo "Not correct format"    
    exit 1 
  fi

#!/bin/bash
MDAYS=(0 31 29 31 30 31 30 31 31 30 31 30 31)

function valid-mm-dd ()
{
     MONTH=${1%-*}
     DAY=${1#*-}
     MONTH=${MONTH#0}
     DAY=${DAY#0}

     [[ $MONTH =~ ^[0-9]{1,2}$ ]] || return
     [[ $DAY =~ ^[0-9]{1,2}$ ]] || return
     (( MONTH > 0 && MONTH < 13 )) || return
     (( DAY > 0 && DAY <= MDAYS[MONTH]))  || return
}
DATE1=$1
DATE2=$2

if valid-mm-dd $DATE1 && valid-mm-dd $DATE2
then
   echo "Correct format"
   echo "DATE1 = $DATE1"
   echo "DATE2 = $DATE2"
else
   echo "Not correct format"
   exit 1
fi