copydetect vs semdup

copydetect is a free tool for comparing code directories and producing an HTML report that highlights matching code slices. It uses Winnowing document fingerprinting, an approach also used by MOSS, and Pygments tokenization for the 500-plus languages Pygments can detect and tokenize. Users can compare test directories with reference directories such as previous submissions, and exclude boilerplate directories from matches. Noise, guarantee and display thresholds adjust what is detected and shown in reports. Install the package with pip; it requires Python 3.7 or later. The command-line tool recursively searches supplied directories, while its Python API supports comparisons and HTML report generation. Reports can be saved to a specified path, highlighted code can be truncated, and custom CSS can be linked. Configuration is available through command-line arguments or a JSON file. The package is MIT-licensed and classified for Education with Beta development status. Its documentation cautions that it may not catch plagiarism designed to evade detection and that a match does not establish that plagiarism occurred.

semdup has no write-up on Specifiction yet; its figures are above.