shell date last month first day of last month last day of last month

date.sh

CT='2019-02-31' # init date   **When LAST DAY (end of month)**

date -d "$CT" +%Y-%m-%d

date -d "$CT last month" +%Y-%m-%d # terrible last month


# last month day 1
date -d "$(date -d "$CT" +%Y-%m-01) last month" +%Y-%m-%d #fixed
# -2 month
date -d "$(date -d "$CT" +%Y-%m-01) -2 month" +%Y-%m-%d
# -3 month
date -d "$(date -d "$CT" +%Y-%m-01) -3 month" +%Y.%m


# last day of last month
date -d "$(date -d "$(date -d "$CT" +%Y-%m-01) last day")" +%Y-%m-%d