UNIX for Dummies Questions & Answers

#! /bin/ksh
# gerry.sh
# input  071205
# output Dec 07 2005
#

# Base date is Oct 19, 2005.
BASE=051019

while read line
do
        DAY=${line%????}
        line=${line#$DAY}
        MON=${line%??}
        YR=${line#??}

        case "$MON" in
        "01") mon=Jan ;;
        "02") mon=Feb ;;
        "03") mon=Mar ;;
        "04") mon=Apr ;;
        "05") mon=May ;;
        "06") mon=Jun ;;
        "07") mon=Jul ;;
        "08") mon=Aug ;;
        "09") mon=Sep ;;
        "10") mon=Oct ;;
        "11") mon=Nov ;;
        "12") mon=Dec ;;
        esac

        
        thisdate=${YR}${MON}${DAY}
        if [[ $thisdate < $BASE ]] ; then
        echo "$mon $DAY $YR is newer"
        else
        echo "$mon $DAY $YR is older"
        fi ;
done < gerry.txt
exit 0