To dump a single schema to disk
exp <user>/<password> FIlE=scott.dmp OWNER=scott
dump a specific table:
exp SYSTEM/password FIlE=expdat.dmp TABLES=(scott.emp,hr.countries)
Note: the above command uses two users : scott and hr
Dump file for Only one user
exp <user>/<password> FILE=scott.dmp TABLES=(emp,dept)
