fsz

fsz (File/Folder Size) is a fast, interactive terminal disk usage analyzer written in Rust. Point it at a directory and it scans the tree in parallel, then drops you into a keyboard-driven TUI where you can drill down into whatever is eating your disk — biggest folders first, every step of the way.

Features

• Parallel scan. Traversal runs on ignore's worker pool on a dedicated thread, saturating your disk while a live spinner reports entries and bytes seen so far.
• On-disk sizes, not apparent sizes. Each file is measured by its allocated size (st_blocks × 512), so the totals reflect what the filesystem actually spends — sparse files and block rounding included.
• Hardlink-aware. Files sharing an inode are counted once, so totals don't double-count hardlinked content.
• Interactive navigation. Built on ratatui. Every directory lists its children largest-first, each with a proportional size bar. Descend, step back up, and the folder you came from stays highlighted.
• Delete from the TUI. Hit Ctrl + D to remove the selected file or folder (recursively) right where you spotted it, behind a confirmation prompt — the size totals update instantly, no rescan needed.
• Single static binary. No runtime, no interpreter — just cargo build --release.

Installation

Install script (macOS & Linux)

The quickest way to get fsz is the install script, which detects your OS (macOS or Linux) and architecture (Apple Silicon / ARM64 or Intel / x86_64), downloads the latest prebuilt binary, and installs it to /usr/local/bin:

curl -fsSL https://raw.githubusercontent.com/kgantsov/fsz/main/install.sh | bash

Or download and run it manually if you'd rather inspect it first:

curl -fsSLO https://raw.githubusercontent.com/kgantsov/fsz/main/install.sh
bash install.sh

The script may prompt for sudo to write to /usr/local/bin. Once it finishes, run fsz --help to verify.

Build from source

Requires a Rust toolchain (edition 2024). Works on any supported Unix-like system.

git clone <repo-url> fsz
cd fsz
cargo build --release
# binary lands at ./target/release/fsz

Platform note: fsz currently uses Unix inode/block metadata (st_dev, st_ino, st_blocks) and targets Unix-like systems (macOS, Linux). Windows is not supported yet.

Usage

fsz [PATH]

PATH defaults to the current directory. fsz scans the whole tree first (with a progress spinner), then opens the interactive view.

fsz              # analyze the current directory
fsz ~/Downloads  # analyze a specific directory
cargo run -- .   # run from source

Unlike tools that honor .gitignore, fsz deliberately walks everything — ignored and hidden files included — so the totals reflect real disk usage.

Keys

Key	Action
↑ / k	Move selection up
↓ / j	Move selection down
→ / l / Enter	Enter the selected directory
← / h / Backspace	Go back to the parent directory
PgUp / PgDn	Move selection up / down by a page
Home / End	Jump to the first / last entry
Ctrl + D	Delete the selected entry (asks first)
q / Esc	Quit (asks for confirmation)

Warning: Ctrl + D deletes permanently — files and folders are removed from disk (not moved to Trash), and directories are deleted recursively. There is a confirmation prompt, but no undo.

Development

cargo run -- .           # run against a directory
cargo build --release    # optimized build
cargo clippy             # lint
cargo fmt                # format
cargo test               # tests (none yet)