In some situation you have to load the data whenever a CSV/Text file appears in a folder. The files will be of same structure i.e. having same number of fields, same delimiting char, but the filenames will be changing.
These files could be generated by a third party program running in the
same computer or on a different computer (might be running Unix o/s) or
received through FTP.
The Folder Polling feature in Data Loader will repeatedly check to see if the files which matches a particular pattern, mentioned by you, have appeared in the specified folder.
And as soon as files appear Data Loader will load the data from these files into target table residing in any database (Oracle, MySQL, MS SQL Server, MS Access, Foxpro, Visual Foxpro, Text). After loading, the files are renamed to prevent loading the contents again.
How often Data Loader will watch a folder is determined by the interval you specify, a typical interval might be 1 Minute or every 1 hour or every 6 hours.
You can check the progress such as which files have been loaded and how many rows are loaded from which file and whether any errors have occurred in the log file.
This feature is available only in Professional and Enterprise Edition.