how to export oracle database to a flat file

I want to export oracle(version 9.2.0.1) database to a flat file. How can I do that? Is there any free tools for that? Found a tool called data loader but it is a commercial one.

you want to export the entire database into flat file ? why ?

Actually I want to port my oracle database to postgres. To do that I found some forum saying need to take a oracle database to flat file and then import it from postgres.

use export utility and store the data definitions in a flat file

Better use some third party tool for the purpose of migration.

You can try this.

Visit postgresql.org and search for ora2pg. you may find some information

You can Export the DDL and its Data using Oracle SQL Developer also.

Navigate to Tools -> Export DDL (and Data), select the database instance and save.