Strata

Find out where your disk space actually went.

Strata scans the folders you point it at and opens a single self-contained HTML dashboard: what's eating your space, which files are byte-identical copies of each other, what's enormous, and what you haven't touched in years.

It never moves, deletes, renames, or modifies a single file. It only looks.

Pure Python standard library — no dependencies, no build step, no server, and nothing ever leaves your machine.

Install and run

You need Python 3.11 or newer. That's the whole list — no pip install, no virtualenv, no dependencies.

git clone https://github.com/saltasaurus/fs-audit.git
cd fs-audit
python strata ~/Documents ~/Pictures

Pass the folders you want scanned. Strata writes outputs/audit.html and opens it in your browser. Re-run any time to refresh. A whole-profile scan takes a few minutes; most of that is hashing files that might be duplicates.

One file, no clone

Download strata.pyz from the latest release and run it:

python strata.pyz ~/Documents

One file with everything inside it, dashboard template included. The same file works on Windows, macOS, and Linux — anywhere Python 3.11 or newer runs. There is nothing to install and nothing to unpack.

Or build it yourself from a clone:

python -m zipapp strata -o strata.pyz

Scanning the same folders often

Rather than retyping paths, list them in a roots.txt in the directory you run Strata from:

cp roots.example.txt roots.txt

C:/Users/YourName/Documents/
D:/Projects/
/mnt/c/Users/YourName/          # WSL mount

Use forward slashes on every platform; blank lines and # comments are ignored. Then run with no arguments — python strata — and it picks the file up. Explicit arguments always win over the file.

roots.txt is git-ignored, so your folder paths never end up in a commit.

Options

Flag	Effect
-o PATH, --output PATH	Write the report somewhere else (default outputs/audit.html)
--no-open	Write the report but don't launch a browser
-v, --verbose	Name every file the scan couldn't read

If a scan ends by reporting files it couldn't read, they're almost always paths longer than Windows' 260-character limit — deep caches from game launchers and build tools are the usual source. Those files aren't counted in any total.

What you get

Storage Map

A drill-down treemap of your entire folder tree. Tiles are sized by how much the folder holds and coloured by what's inside it. Click a tile to go deeper, use the breadcrumb to climb back out — you bottom out at the actual files.

Duplicates

Files with byte-identical content, grouped into sets — matched by content hash, not by filename, so invoice.pdf and invoice (1).pdf are caught, and two different files that happen to share a name are not.

Strata groups files by size first and only hashes the ones that share a size, because a file with a unique size can't possibly have a twin. That skips re-reading the overwhelming majority of your disk.

It also finds near-duplicates — drafts and edited copies whose text is similar but not identical. The copy in the shortest path is marked the recommended keeper. Tick the ones you don't want and export a plain-text list to act on yourself.

Old & Unused

Everything you haven't touched in a long time, with a live slider from 30 days to 2 years. Folders written in one go — a photo import, an old tax year — collapse into a single row instead of flooding the list with hundreds of files that all share a timestamp.

Empty & Junk

Empty folders, zero-byte files, and OS clutter (Thumbs.db, .DS_Store, desktop.ini). Only the outermost folder of an empty chain is listed, so one entry covers the whole dead branch. Folders that merely look empty because Strata skipped their contents are never flagged.

Large Files

Every file at or above 1 GB, sortable by name, category, size, or age, with search.

Nothing is ever deleted

Strata is an auditor, not a cleaner. It shows you what to consider removing and leaves the removing to you.

• The only file it ever writes is outputs/audit.html.
• Symlinks are never followed.
• Folders matching a skip rule are never even opened — by default that's C:/Windows, node_modules, .git, .venv, AppData, and similar noise.
• The report is a single self-contained HTML file. No telemetry, no network calls, no accounts.

The "Export review list" button gives you a text file of the copies you flagged. Nothing acts on it but you.

Optional tuning

Everything below is optional — strata/config.py has sensible defaults. The knobs worth knowing about:

Setting	Default	What it does
SKIP_PATHS	Windows, node_modules, .git, …	Any path containing one of these substrings is never traversed
LARGE_FILE_BYTES	1 GB	The "Large Files" cutoff
OLD_FILE_DAYS	365	What counts as untouched
NEAR_DUP_THRESHOLD	0.8	How similar two files must be to be called near-duplicates. Lower toward 0.6 for looser matching
CATEGORY_EXTENSIONS	—	Which file extensions count as Photos, Videos, Documents, …

A note on ages: "last touched" uses each file's modification time. Access time looks like the better signal but is unreliable in practice — often disabled outright, and bumped by backup tools and search indexers that never really "opened" anything.

License

MIT — see LICENSE.