Shell Programming and Scripting

#!/bin/ksh
export yearmonth_date=$1
print_usage() {
   echo "usage: ${0##*/} <yearmonth_date> \n" \
               "      yearmonth_date        a yearmonth_date value in the format  YYYYMM" 1>&2
   exit 1
}
# check for valid parameters
if [[ $# -eq 1 ]]; then
     yearmonth_date =$1
else
   print_usage
fi
year=$(echo "$yearmonth_date" | cut -c1-4)
month=$(echo "$yearmonth_date" | cut -c5-6)
day='01'
curr_month_date=$year-$month-$day
echo $curr_month_date

>ksh get_curr_date.ksh 200904
get_rcurr_date.ksh[11]: yearmonth_date:  not found.
2009-04-01

yearmonth_date =$1