mapsize

An interactive, full-terminal disk usage analyser built around a live, navigable treemap. Think WinDirStat + ncdu + WizTree, in one Go binary that runs over SSH.

mapsize is a working name; branding lives in internal/brand.

Status

Milestones 0.1–0.8 are implemented; 0.9 (hardening) is in progress. See ROADMAP.md for detail and PERFORMANCE.md for measured numbers.

What it does

• Live treemap. A squarified, space-filling treemap fills the terminal and grows while the scan runs. Directories show nested previews of their contents; colours are file categories (video, archives, disk images, code, …). Items too small to draw collapse into a "N smaller items" block until you zoom in.
• Spatial navigation. Arrow keys move to the block that is actually to the left/right/above/below. Enter inspects, Space zooms in, Backspace zooms out, Home returns to the root. The selection survives rescans, resizes and filtering.
• Resizes properly. Every resize recomputes the layout for the new geometry (it never stretches the old one); large terminals get a side panel, small ones a compact layout, tiny ones a polite message.
• Search and filter with a small query language — the treemap shows only matching data: ubuntu · *.iso · size > 5GB · ext IN (iso,qcow2,vmdk) · age > 365d · path contains cache AND NOT type = dir · owner = andy
• Investigation views (Tab): directory list, file types, top lists (largest files/dirs, oldest/newest large files, most entries, sparse and hard-linked files), scan information with every error, duplicates.
• Honest numbers. Allocated vs logical size, hard links counted once, sparse files flagged, permission errors and skipped areas always shown; incomplete totals are labelled as such.
• Snapshots: save a scan, reopen it instantly, compare two — the treemap colours growth and shrinkage.
• Safe with hostile filenames: control characters and escape sequences in names are displayed escaped and never reach the terminal.

Keys

Key	Action
↑ ↓ ← → / hjkl	move spatially through the map
Enter	item information
Space / →	zoom into directory
Backspace / ←	zoom out
Home	scan root
/	search / filter (Esc clears)
Tab, Shift+Tab, 1–7	switch views
x, g, e	file types, top lists, scan info & errors
D	find duplicates
a	toggle allocated / logical size
c, o	copy path, reveal in file manager
d	move to trash (asks; disabled with --read-only)
s, r	save snapshot, rescan
T	cycle theme
?	help
Ctrl+C	cancel scan, then quit
q	quit

Mouse: click selects, double-click zooms, right-click inspects, wheel zooms the map or scrolls lists. Everything works without a mouse (--no-mouse).

Install

go install github.com/andydixon/mapsize/cmd/mapsize@latest
# or
make build   # → bin/mapsize

Usage

mapsize .                       # scan and explore interactively
mapsize --read-only /mnt/evidence
mapsize /srv --save srv.msz     # explore, and save a snapshot when done
mapsize srv.msz                 # reopen a snapshot (no rescan)
mapsize --compare old.msz new.msz

# non-interactive
mapsize /srv --top 50
mapsize /srv --largest-files 20
mapsize /srv --json --depth 3
mapsize /srv --csv > inventory.csv
mapsize /srv --no-ui --save snapshot.msz
mapsize /srv --duplicates --no-ui

Sizes and units

• By default sizes are allocated (disk usage, like du); --apparent switches to logical size. Both are shown in the info modal.
• Units are IEC (KiB, MiB, GiB — powers of 1024) everywhere; --si switches everything to SI (kB, MB, GB — powers of 1000). Never mixed.
• Hard links are counted once (first path seen); see ARCHITECTURE.md.

Filesystem boundaries and exclusions

• Default: other filesystems are descended (like du), except Linux virtual filesystems (proc, sysfs, cgroup, …) which are never scanned. Mount points are marked.
• --one-file-system / -x: stay on the root's filesystem.
• --follow-symlinks=none|same-filesystem|all (default none). Loops are detected and nothing is counted twice.
• --exclude PATTERN (repeatable): glob on entry name, or a path prefix if the pattern contains a separator. Exclusions are always shown in the UI.

Configuration

Optional JSON file at $XDG_CONFIG_HOME/mapsize/config.json (macOS: ~/Library/Application Support/mapsize/config.json, Windows: %AppData%\mapsize\config.json):

{
  "workers": "balanced",
  "theme": "default",
  "units": "iec",
  "excludes": ["/proc", "*.tmp"],
  "category_colors": {"Video": "#e06c75"},
  "extension_colors": {"qcow2": "#c678dd"}
}

Colour

Colour support is auto-detected; --color truecolor|256|16|none overrides it (handy over SSH, where COLORTERM is often not forwarded). Themes: default, dark, high-contrast, mono (--theme, or T to cycle). NO_COLOR is respected. On the Linux console, or with MAPSIZE_ASCII=1, box drawing falls back to ASCII.

Read-only mode

--read-only disables every modifying action and shows READ ONLY in the header. (Saving a snapshot file is still allowed; it writes only where you tell it to.) It does not make mapsize a forensic acquisition tool: scanning uses ordinary filesystem APIs, and duplicate detection reads file content (which may update access times).

Deletion

d moves the selected item to the system trash (freedesktop.org trash on Linux, ~/.Trash on macOS, the Recycle Bin on Windows) after confirmation, using native file operations — never a shell. Permanent deletion is not offered. Trash is unavailable while scanning, for snapshots, and in read-only mode.

Documentation

• ARCHITECTURE.md — design and invariants
• DEVELOPMENT.md — building, testing, profiling
• PERFORMANCE.md — measured results