1. A method for pre-processing entries in a directory listings, comprising: receiving a first directory listings including one or more fields, the one or more fields populated with entries including one or more symbol strings; receiving a second directory listings including one or more fields, the one or more fields of the second directory listings populated with entries including one or more symbol strings; correlating entries in the one or more fields of the first directory listings with entries in the corresponding one or more fields of the second directory listings; identifying entries, in the one or more fields of the first directory listings, which do not correlate with entries in the corresponding one or more fields of the second directory listings; processing the identified entries using a rule set corresponding to the field in which the entry is located; based on the rule set, determining a corresponding confidence level for the processed entries; automatically modifying the processed entries having the corresponding confidence level meeting or exceeding a threshold; and outputting the automatically modified entries for processing.