How do I copy a schema for an instance of Oracle running in a Docker container?
expdp is a command line utility that interacts with the DBMS_DATAPUMP API. You run it on the host OS, not from within another client.

https://docs.oracle.com/cd/B19306_01/appdev.102/b14258/d_datpmp.htm#BABHBEHH


  See Also:
  Oracle Database Utilities for more information on the concepts behind the DBMS_DATAPUMP API, how it works, and how it is implemented in the Data Pump Export and Import utilities


https://docs.oracle.com/cd/B19306_01/server.102/b14215/dp_overview.htm#i1009203