dcd review
A focused, self-hosted option for fuzzy duplicate checks in CI.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
dcd is an open-source command-line tool for finding repeated and near-duplicate code in software projects. It is aimed at developers and teams that want a lightweight, self-hosted check for repositories, particularly in continuous integration workflows. The tool can compare a single file with a codebase, detect duplicates within the same file, and report matches in text, JSON, HTML, or PBM formats.
Its main strength is configurable fuzzy matching. dcd uses simhash distance and can tolerate gaps caused by inserted or deleted lines, as well as holes created by modified lines. Configurable ignored blocks and ignore files help exclude selected content from scans. For CI, a duplicate-threshold exit code provides a direct way to make detection part of an automated check. These capabilities make dcd more useful than a strict line-for-line duplicate scanner when similar code has been lightly edited or rearranged.
The project is free, open source, and self-hosted, with native binaries and source installation instructions for macOS and Linux. Its repository scan scope and command-line workflow suit teams comfortable integrating tools into scripts and build pipelines. The trade-off is focus: dcd uses a text-based clone method, has no IDE integration, and does not provide AI features. Windows support was removed in the latest 1.1.0 release, despite older Windows build examples remaining in the README. Choose dcd when simple fuzzy repository checks, configurable tolerances, and CI exit codes are the priority; consider an alternative when IDE workflows, Windows support, or broader analysis capabilities matter more.
dcd pros and cons
- Where it wins
- Simhash matching tolerates inserted, deleted, and modified lines
- JSON, HTML, text, and PBM outputs support varied reporting needs
- Duplicate-threshold exit codes fit continuous integration workflows
- Where it doesn't
- Text-based detection is narrower than broader clone-analysis methods
- No IDE integration is provided
- Supported platforms are macOS and Linux
dcd fact sheet, pricing and score →
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