Drop Database

dbca -silent -deleteDatabase -sourceDB cdb1 -sysDBAUserName sys -sysDBAPassword  abcd
Connecting to database
9% complete
14% complete
19% complete
23% complete
28% complete
33% complete
38% complete
47% complete
Updating network configuration files
48% complete
52% complete
Deleting instances and datafiles
66% complete
80% complete
95% complete
100% complete
Look at the log file “/home/cfgtoollogs/dbca/cdb1.log” for further details.

$ more /home/cfgtoollogs/dbca/cdb1.log
[ 2020-04-17 11:26:57.709 CDT ] The Database Configuration Assistant will delete the Oracle instances and datafiles for your database. All information in the database will be deleted. Do you
want to proceed?
[ 2020-04-17 11:26:57.737 CDT ] Connecting to database
DBCA_PROGRESS : 9%
DBCA_PROGRESS : 14%
DBCA_PROGRESS : 19%
DBCA_PROGRESS : 23%
DBCA_PROGRESS : 28%
DBCA_PROGRESS : 33%
DBCA_PROGRESS : 38%
DBCA_PROGRESS : 47%
[ 2020-04-17 11:28:00.106 CDT ] Updating network configuration files
DBCA_PROGRESS : 48%
DBCA_PROGRESS : 52%
[ 2020-04-17 11:28:01.007 CDT ] Deleting instances and datafiles
DBCA_PROGRESS : 66%
DBCA_PROGRESS : 80%
DBCA_PROGRESS : 95%
DBCA_PROGRESS : 100%
[ 2020-04-17 11:28:10.797 CDT ] Database deletion completed.