#!/bin/ksh
					#
					#     kcal - Korn Shell calendar program
					#
					# Process errors
					function error {
					print ${1:-"unexplained error encountered"}
					exit ${2}
					}
					# Check arguments
					if (($# > 0))
					then
					error "Usage: $0" 1
					fi
					# Use environment variable setting or default
					: ${CALFILE:=$HOME/.calfile}
					# Create calendar file if non-existent; flag
					# creation error
					if [[ ! -f $CALFILE ]]
					then
					print "Creating default $HOME/.calfile"
					> $HOME/.calfile || error "$HOME/.calfile: 
					cannot create" 1
					fi
					# Variable declaration/assignment
					typeset DATE= LINE= ENTRY= REPLY="yes" 
					PAGER=$(whence more) CLEAR=$(whence clear)
					# Set trap to not allow interrupts
					trap '$CLEAR; print "aInterrupt ignored - use 
					menu to quit. Press <Return> to continue."; 
					read TMP; $CLEAR' INT QUIT
					# Set EXIT trap - perform cleanup
					trap 'rm -rf /tmp/.FOUND$$ /tmp/.CHANGE$$ 
					/tmp/.DEL$$' EXIT
					# Check the date
					function checkdate {
					while true
					do
					# Prompt for date
					read DATE?"Enter date in mmdd[yy] format (default
					today):"
					case $DATE in
					# Default - use todays date
					"" ) DATE=$(date +%m-%d-%y)
					break ;;
					# Check the given date
					+([0-9]) )
					case ${#DATE} in
					4|6)# Set month to first 2 chars
					typeset -L2 MO=$DATE
					# Check length for year;
					# 4 = mmdd, 6 = mmddyy
					if ((${#DATE} == 6))
					then
					# Set TMP to get date
					typeset -L4 TMP=$DATE
					# Get day
					typeset -R2 DA=$TMP
					# Get year
					typeset -R2 YR=$DATE
					else
					# Get day
					typeset -R2 DA=$DATE
					# Set to current year
					YR=$(date +%y)
					DATE=$DATE$YR
					fi
					# Now check indiv values
					# Day must be in range 01-31
					if ((DA < 01 || DA > 31))
					then
					print "$DA: invalid day 
					format - try again"
					continue
					fi
					# Month must be 01-12
					if ((MO < 01 || MO > 12))
					then
					print "$MO: invalid 
					month format - try again"
					continue
					fi
					# Set date format mm-dd-yy
					DATE=$MO-$DA-$YR
					break ;;
					* )  # Invalid format
					print "$DATE: invalid date 
					format - try again" ;;
					esac ;;
					# Invalid date given
					* ) print "$DATE: invalid format - try again" ;;
					esac
					done
					}
					# Add new calendar entry
					function addentry {
					$CLEAR
					ENTRY="$DATE"
					# For existent entry, just add more data
					COUNT=$(grep -c "^$DATE" $CALFILE)
					if ((COUNT > 0))
					then
					changeentry
					return
					fi
					# Prompt for input
					print "Enter info for $DATE: (enter <Return> by itself
					when finished)"
					while true
					do
					read LINE?"=>"
					if [[ -n $LINE ]]
					then
					ENTRY="$ENTRY,$LINE"
					else
					break
					fi
					done
					# Append to calendar file
					print $ENTRY>>$CALFILE
					# Sort the calendar file
					sort -o $CALFILE $CALFILE
					}
					function formatentry {
					$CLEAR
					typeset IFS="," 
					BORDER="**************************************" 
					BORDER1="*                               *" 
					FILE=$1
					if [[ -s $FILE ]]
					then
					# Open calendar file for reading, and
					# format output
					(exec 0<$FILE
					while read -r ENTRY
					do
					print "$BORDER
$BORDER1"
					set $ENTRY
					typeset -L35 LINE="DATE: $1"
					print "* $LINE*"
					shift
					print "$BORDER1"
					for i
					do
					LINE="$i"
					print "* $LINE*"
					done
					print "$BORDER1"
					done
					print "$BORDER"
					) | $PAGER
					else
					print "No entries found."
					fi
					# Prompt to continue
					until [[ $REPLY = "" ]]
					do
					read REPLY?"Enter <Return> to continue..."
					done
					}
					# Find specific entry
					function findentry {
					$CLEAR
					# Check for entry - put it in temp found file
					grep $DATE $CALFILE >/tmp/.FOUND$$
					# Format found entries
					formatentry /tmp/.FOUND$$
					}
					# Change an entry
					function changeentry {
					# Find specific entry - put it in temp found file
					grep $DATE $CALFILE | tr ',' '12'>/tmp/.FOUND$$
					# Return if no entry was found
					if [[ ! -s /tmp/.FOUND$$ ]]
					then
					$CLEAR
					read TMP?"Entry for $DATE not found - press
					<Return> to continue"
					return
					fi
					# Prompt again for change
					while [[ $REPLY != "" ]]
					do
					read REPLY?"Change/Add to entry for <$DATE>?"
					case $REPLY in
					[yY]* | "" )
					break ;;
					[nN]* )     print "Ok, aborting entry
					change"
					return ;;
					*) print "Invalid reply - try again." ;;
					esac
					done
					# Edit the temporary found file
					${EDITOR:-vi} /tmp/.FOUND$$
					# Remove the specified original entry
					grep -v $DATE $CALFILE > /tmp/.CHANGE$$
					# Put back new change in record format.
					# Add trailing 

					(cat /tmp/.FOUND$$ | tr '12' ',' ; print ) 
					>>/tmp/.CHANGE$$
					# Put back new file
					cat /tmp/.CHANGE$$ > $CALFILE
					# Clean up tmp files
					rm -rf /tmp/.CHANGE$$ /tmp/.FOUND$$
					}
					# Remove specific entry
					function delentry {
					# Look for entry
					grep $DATE $CALFILE >/tmp/.FOUND$$
					# Return if not found
					if [[ ! -s /tmp/.FOUND$$ ]]
					then
					$CLEAR
					read TMP?"Entry for $DATE not found - press
					<Return> to continue"
					return
					fi
					# Prompt to delete
					while [[ $REPLY != "" ]]
					do
					read REPLY?"Delete entry for <$DATE>?"
					case $REPLY in
					[yY]* | "")
					break ;;
					[nN]*)
					print "ok, aborting delete";
					return ;;
					*) print "Invalid reply - try again."
					;;
					esac
					done
					# Merge changes - put them in temporary file
					grep -v $DATE $CALFILE > /tmp/.DEL$$
					# Put back new file
					cat /tmp/.DEL$$ > $CALFILE
					# Clean up tmp files
					rm -rf /tmp/.DEL$$ /tmp/.FOUND$$
					}
					Set menu selection prompt
					PS3="Enter selection or <Return> for default menu:"
					# Display menu
					while true
					do
					$CLEAR
					select i in "Add calendar entry" "Delete calendar
					entry" "Change calendar entry" "Find calendar entry" "List
					all calendar entries" "List todays calendar entry" "Exit"
					do
					case $i in
					"Add calendar entry")
					checkdate
					addentry
					$CLEAR ;;
					"Delete calendar entry")
					checkdate
					delentry
					$CLEAR ;;
					"Change calendar entry")
					checkdate
					changeentry
					$CLEAR ;;
					"Find calendar entry")
					checkdate
					findentry
					$CLEAR ;;
					"List all calendar entries")
					formatentry $CALFILE
					$CLEAR ;;
					"List todays calendar entry")
					DATE=$(date +%m-%d-%y)
					findentry
					$CLEAR ;;
					"Exit")
					exit ;;
					* )   print "aInvalid selection c"
					read TMP?"- press <Return> to
					continue"
					$CLEAR
					continue ;;
					esac
					done
					done