Oracle 11g production database copy to USB drive What is the correct commands for backing up a production Oracle 11g database (while still running) to an external USB drive or different directory.

I am new to Oracle and but have experience with SQL Server.  Essentially, I am looking for the equivalent of a COPY_ONLY backup - something which will not interfere with the existing backup process.

The goal is to take the backup offsite and use it to develop migration scripts for a new application.  Any insights would be appreciated.
To get a consistent single-file snapshot of a running Oracle instance DataPump Export can be used.

You need to have access to the server's filesystem (or a shared filesystem) in order to copy the resulting dump file.

The process would be to 


run expdp (for one or multiple schemas)
copy the dump file to the USB stick
run impdp to import the dump into the development database