Getting Started

中文

Goal: run a scan with minimal setup, and understand the shape of the output.

0) Prerequisites

• Rust toolchain 1.92.0 (pinned by rust-toolchain.toml)
• (Optional) Node.js >= 22 (only if you want to install/build via npm)
• (Optional) Git: by default we respect .gitignore (and .git/info/exclude / global ignores when in a Git repo), and when available we use git ls-files to speed up file collection. Use --no-gitignore to include ignored files.

1) Run from source (recommended)

From the repo root:

cargo build --release -p dup-code-check
./target/release/dup-code-check --help

Or build via npm and run:

npm install
npm run build
./bin/dup-code-check --help

Or run via npx (will compile on first run if needed):

npx dup-code-check --help

Security note: building runs a native build (Cargo), which may execute dependency build scripts. Depending on how you install, this may run during postinstall or on first run. Use --ignore-scripts / npm_config_ignore_scripts=true if you need to avoid running install scripts (see Installation & Build).

2) Scan a directory: duplicate files (default)

dup-code-check .

In text mode you’ll see:

• duplicate groups: N
• one line per group: hash=... normalized_len=... files=...
• then a list of - [repoLabel] path

normalized_len is the byte length after removing ASCII whitespace (not the original file size).

3) Scan multiple roots: only cross-root duplicates

dup-code-check --cross-repo-only /repoA /repoB

--cross-repo-only filters out groups that only occur within a single root.

Roots are exactly the paths you pass; --cross-repo-only only works with 2+ roots and does not auto-detect Git repos.

4) Suspected duplicate code spans (with line ranges)

dup-code-check --code-spans --cross-repo-only /repoA /repoB

Output contains:

• duplicate code span groups: N
• preview=... for each group
• occurrences as path:startLine-endLine

This is a lightweight detector: no AST parsing; it uses normalization + matching/fingerprints.

5) JSON output (for CI / post-processing)

dup-code-check --json --stats --strict .

• --json: machine-readable output
• --stats: includes scanStats (or prints to stderr in text mode)
• --strict: exits non-zero if the scan was incomplete (e.g. permission errors, traversal errors, budget abort)

Tip: non-fatal skips still exit 0; use --stats (check stderr in text mode) and --strict to fail CI on incomplete scans.

For a complete field reference, see Output & Report.