heft

Fast disk usage scanner with mtime tracking. Indexes a directory tree into an LMDB database, then queries it instantly.

Similar to duc, but faster — heft parallelizes filesystem stat calls across a thread pool and writes results in batched LMDB transactions.

Install

cargo install heft

Usage

# Index a directory
heft index /home/user

# Index without crossing filesystem boundaries
heft index / --one-file-system

# Exclude paths
heft index /home --exclude .cache --exclude target
heft index /home --exclude-from patterns.txt

# Show summary
heft info

# List a directory (sorted by size, largest first)
heft ls
heft ls /home/user/Documents

# Export as JSON
heft json
heft json --compress zstd --output tree.json.zst

Options

Flag	Description
`-d, --database <path>`	Database path (default: `~/.heft.db`)
`--map-size-gib <n>`	LMDB map size in GiB (default: 4)
`--threads <n>`	Worker thread count (default: all cores)
`--one-file-system`	Don't cross mount boundaries
`--exclude <pattern>`	Exclude paths containing `<pattern>`
`--exclude-from <file>`	Read exclude patterns from file
`-v, --verbose`	Print each file as it's scanned

Database

heft stores results in LMDB at ~/.heft.db. The database is always re-generable via heft index, so it uses WRITE_MAP + MAP_ASYNC flags for speed (no fsync). Override the path with -d.

AI Disclaimer

This project was built with the assistance of AI tools, specifically Claude Opus 4.6 (Anthropic) and Gemini Pro Preview 3.1 (Google). AI-generated code may contain bugs, security issues, or other defects. This software is provided as-is with no warranty. Use at your own risk.