How can I get the 1st and last date of the previous month in a Bash script?

Question

I have scheduled a Bash script to run on the 1st of the month but I need to create 2 variables in it with the 1st and last date of the previous month, whatever those may be.

Answer 1

This can be done in two lines, tweak date format to suit.

START_LAST_MONTH=$(date "+%F" -d "$(date +'%Y-%m-01') -1 month")
END_LAST_MONTH=$(date "+%F" -d "$START_LAST_MONTH +1 month -1 day");

#Test Code
echo START_LAST_MONTH=$START_LAST_MONTH
echo END_LAST_MONTH=$END_LAST_MONTH

Running gives:

START_LAST_MONTH=2018-09-01
END_LAST_MONTH=2018-09-30