-- 1. export the source database

exp dbaUser/passCode@sourceDb full=y file=somefile.dmp

-- 2. Prepare the target database
make sure u have the tablesepaces same as target (else, u have to do the import one schema at a time).
create the users.

-- 3. do the import

imp dbaUser/passCode@targetDb full=y file=somefile.dmp

-- if you dont have the same tablespaces or want the objects in new tablespaces

dbaUser/passCode@targetDb file=somefile.dmp fromuser=user1_in_sourceDb touser=user1_in_targetdb

dbaUser/passCode@targetDb file=somefile.dmp fromuser=user2_in_sourceDb touser=user2_in_targetdb