# disk-checker

Fast Ubuntu-friendly CLI for scanning folders, checking file sizes, hashing the first chunk of same-size files, and reporting possible duplicates plus symlinks, hard links, special files, and scan errors.

## Install Rust on Ubuntu

```bash
sudo apt update
sudo apt install -y build-essential curl
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
source "$HOME/.cargo/env"
```

## Build

```bash
cargo build --release
```

The binary will be at:

```bash
target/release/disk-checker
```

## Usage

Scan the current directory:

```bash
disk-checker
```

Scan one or more paths:

```bash
disk-checker ~/Downloads /mnt/shared
```

Use JSON for scripts:

```bash
disk-checker ~/Downloads --json
```

Hash a larger first chunk before grouping possible duplicates:

```bash
disk-checker ~/Downloads --hash-bytes 8MiB
```

Follow symlinks while still reporting them separately:

```bash
disk-checker ~/Downloads --follow-links
```

Verify possible duplicates with a full-file hash pass:

```bash
disk-checker ~/Downloads --verify-full
```

Limit hashing workers:

```bash
disk-checker ~/Downloads --threads 4
```

## Notes

- By default, duplicate results are **possible duplicates**: same file size plus same first `1MiB` BLAKE3 hash.
- This is intentionally fast because it avoids reading whole files unless you pass `--verify-full`.
- Symlinks are not followed by default to avoid surprises and cycles.
- Hard link groups are reported separately because they are multiple paths to the same inode, not extra disk copies.
- Hidden files and gitignored files are included; this is a disk scanner, not a source-code search tool.