UTL_File to read directories on client machines
I am afraid UTL_FILE can only read server side directories and cannot read directories in client machines – unless you want to install local oracle instances on each machine (and that is not a wise solution either). A better option will be to use the CREATE EXTERNAL feature tables that uses SQL*LOADER and can read from flat files. The external tables can also be used in your SQL statements. Secondly keep in mind, UTL_FILE is going away and CREATE DIRECTORY is the way to go.