Track disk space growth over time. dwatch takes periodic snapshots of directory sizes and shows you what is growing — by bytes, percentage, or daily rate.

Works on macOS and Linux.

Requires Go 1.21+.

git clone <repo>
cd dwatch
make install

This builds the binary, installs it to /usr/local/bin/dwatch, and copies a default config to ~/.dwatch/dwatch.conf.

make uninstall   # remove the binary

Pre-built binaries are on the GitHub releases page (linux arm64/amd64, darwin arm64/amd64 for Apple Silicon and Intel Mac).

# Example: Linux arm64
curl -sL https://github.com/silverbucket/dwatch/releases/download/v1.3.0/dwatch_v1.3.0_linux_arm64.tar.gz | tar -xz
sudo install -m 755 dwatch /usr/local/bin/dwatch

dwatch scan                        # take a snapshot
dwatch status                      # largest dirs + what grew since last scan
dwatch diff --since 1w             # full change table for the past week
dwatch top --since 1m              # rank directories by growth this month
dwatch top --since 1d --by pct    # catch small dirs growing fast

dwatch scan walks the filesystem, computes the allocated size of each directory using block counts (like du — sparse files and VM disk images report correctly), and saves a timestamped JSON snapshot to ~/.dwatch/.

The reporting commands — status, diff, top, alert — compare any two snapshots. Snapshots are plain JSON files; prune them by deleting files directly.

Run scan automatically on a schedule, then query on demand or alert via cron.

MAILTO=you@example.com

# Snapshot every 3 hours
0 */3 * * *   /usr/local/bin/dwatch scan --quiet

# Alert at 8am if anything grew >500 MB overnight
0 8 * * *     /usr/local/bin/dwatch alert --since 1d --threshold 500mb

# Weekly growth report every Monday
0 9 * * 1     /usr/local/bin/dwatch top --since 1w --limit 20

cron sends MAILTO an email when a command exits non-zero — so alert will mail you only when the threshold is exceeded.

Walk the filesystem and save a snapshot.

Default skip paths — macOS: /dev, /System/Volumes, /net, /home · Linux: /proc, /sys, /dev, /run

dwatch scan --root /Users --depth 4
dwatch scan --skip /Volumes/Backup
dwatch scan --quiet

Quick overview: largest directories in the latest snapshot and what grew.

dwatch status
dwatch status --since 1w
dwatch status --limit 10

Full change table between two snapshots.

dwatch diff --since 1w
dwatch diff --since 2026-05-01 --min-change 100mb
dwatch diff --all --limit 0

Rank directories by growth within a time window.

--by pct is useful for catching directories that are small but growing fast — a cache that doubled in size ranks above a large directory that barely moved.

dwatch top --since 1w
dwatch top --since 1d --by pct
dwatch top --since 1m --by rate --limit 10

Exit 1 if any directory grew past a threshold. Silent on success — safe for scripts.

dwatch alert --threshold 1gb --since 1d
dwatch alert --threshold 500mb

make install copies a default config to ~/.dwatch/dwatch.conf. Edit it to set your own defaults — CLI flags always take precedence.

data_dir  = ~/.dwatch
scan_root = /
scan_depth = 5
scan_skip = /dev, /System/Volumes, /net, /home

scan_skip is applied at report time, not just at scan time. Adding a path to the skip list removes it from diff, top, status, and alert output immediately — even for old snapshots — without needing to re-scan.

Released under the GNU General Public License v3.0.

Written by Nick Jennings.