Ferret is a copy-detection program, locating duplicate text or code in multiple text documents or source files: it is designed to detect copying (collusion) within a given set of files. Duplicate text is detected by looking for common trigrams of words or tokens.


Ferret is available for the command-line, as:


Ferret was created at the University of Hertfordshire by the one-time Plagiarism Detection Group and developed by Ruth Barrett, Bob Dickerson, Caroline Lyon and James Malcolm. The program was extended to work with the Chinese language by Jun-Peng Bao, and Pam Green has shown how to extract more precise information on duplicate material from Ferret’s output. This version of Ferret has been implemented by Peter Lane.


Ferret is copyright the University of Hertfordshire, 2004-2018.

Ferret is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

Ferret is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with Ferret. If not, see http://www.gnu.org/licenses/.