Shell Programming and Scripting

#!/bin/ksh

monthend()
{
    if [[  -z "$1" ]] ; then
	    set -A arr $(cal | tail -3 | tr -s '\n'  ' ')
	else
	    set -A arr $(cal $1 $2| tail -3 | tr -s '\n'  ' ')
	fi    
	p=$((  ${#arr[*]} % 7  ))
	element=0
	case "$p" in 
		'0') element=$(( ${#arr[*]} - 2 ));;
		'1') element=$(( ${#arr[*]} - 3 ));;
		'2') element=$(( ${#arr[*]} - 1 ));;
		'3') element=$(( ${#arr[*]} - 1 ));;
		'4') element=$(( ${#arr[*]} - 1 ));;
		'5') element=$(( ${#arr[*]} - 1 ));;
		'6') element=$(( ${#arr[*]} - 1 ));;
    esac                            
    echo ${arr[element]}

}
# example current month monthend:
cal       # show the calendar
monthend  # print monthend 

# for all of 2008 

for i in 1 2 3 4 5 6 7 8 9 10 11 12
do
   cal $i 2008
   monthend $i 2008
done

#usage:
monthend | read thismonthend