Shell Programming and Scripting

 
bash> echo date +%m
bash> 03
 
bash> month=`date +%m`
bash> lmonth=$month-1
bash> echo $lmonth
bash>2

printf "%02d\n" $lmonth

mon=$(date +%m)
arr=(12 1 2 3 4 5 6 7 8 9 10 11 12)
last_mon=${arr[$((mon - 1))]}
printf "%d%02d\n" $(date +%Y) $last_mon

 
typeset -RZ2 month
month=`date +%m`
year=`date +%Y`
month=$(($month-1))
if [ $month -lt 1 ]; then
        year=$(($year-1))
        month=12
fi
echo ${year}${month}