I need a scipt that gets the prior month and writes it to a variable. After that I need to check if the month is a quarter month (Mar,Jun,Sep,Dec) and if it is call another script and pass the month year as an argument in the format "Sep-2020". If its not a quarter month call another script.

```
monthyear="Sep-2020"

if [[ quartermonth ]]
then runscript1 $monthyear
elif [[ not a quartermonth ]]
then runscript2 $monthyear
fi

```