Flexible enumeration can be achieved by giving an Enumeration=filter modifier to a RootNode URL. The filter is a program which takes URLs on standard input, and writes new RootNode URLs on standard output.
The output format is different than specifying a RootNode URL in a Gatherer configuration file. Each output line must have nine (9) fields separated by spaces. These fields are:
URL URL-Max URL-Filter-filename Host-Max Host-Filter-filename Access Delay Depth Enumeration-Program
These are the same fields as described in section 4.3. Values must be given for each field. Use /dev/null to disable the URL-Filter-filename and Host-Filter-filename. Use /bin/false to disable the Enumeration-Program.