#!/bin/bash
# normdate--Normalizes month field in date specification to three letters,
#  first letter capitalized. A helper function for Script #7, valid-date.
#  Exits with 0 if no error.

monthNumToName()
{
    # Sets the 'month' variable to the approrpriate value.
    case $1 in
        1 ) month="Jan"  ;;  2 ) month="Feb"  ;;
        3 ) month="Mar"  ;;  4 ) month="Apr"  ;;
        5 ) month="May"  ;;  6 ) month="Jun"  ;;
        7 ) month="Jul"  ;;  8 ) month="Aug"  ;;
        9 ) month="Sep"  ;;  10 ) month="Oct"  ;;
        11 ) month="Nov"  ;;  12 ) month="Dec"  ;;
        * ) echo "$0: Unknown month value $1" >&2
            exit 1
    esac
    return 0
}

# BEGIN MAIN SCRIPT--DELETE OR COMMENT OUT EVERYTHING BELOW THIS LINE IF
#  YOU WANT TO INCLUDE THIS IN OTHER SCRIPTS.
# =================
# Input validation
if [ $# -ne 3 ] ; then
    echo "Usage: $0 month day year" > &2
    echo "Formats are August 3 1962 and 8 3 1962" >&2
    exit 1
fi
if [ $3 -le 99 ] ; then
    echo "$0: expected 4-digit year value." >&2
    exit 1
fi

# Is the month input format a number?
if [ -z $(echo $1|sed 's/[[:digit:]]//g') ] ; then
    monthNumToName $1 
else
# Normalize to first 3 letters, first upper- and then lowercase.
    month="$(echo $1|cut -c1|tr '[:lower:]' '[:upper:]')"
    month="$month$(echo $1|cut -c2-3 | tr '[:upper:]' '[:lower:]')"
fi

echo $month $2 $3

exit 0