Cloning a Db2 database within a single instance
This is a minimial example of copying a database (test) to a into a new database (test2)

db2 create database test
db2 backup database test to /tmp
db2 restore database test from /tmp into test2
db2 connect to test2


   Database Connection Information

 Database server        = DB2/LINUXX8664 11.1.3.3
 SQL authorization ID   = DB2INST1
 Local database alias   = TEST2