How I Freed 15GB on My 256GB MacBook and Made an External SSD My Primary Storage (With 46 Automation Scripts)

Shravan Omanakuttan — Sun, 26 Jul 2026 10:59:55 +0000

My MacBook's internal storage was full. Not "almost full" — full. No more space for new projects, no room for dependencies, constant "Your disk is almost full" alerts.

I had a 1TB external SSD sitting on my desk doing nothing.

So I built a system to use the SSD as my Mac's primary storage — transparently, automatically, with a full terminal menu and 18 scheduled automation scripts running in the background.

Here's exactly how I did it, and how you can too.

The Problem

256GB internal SSD. Here's what was eating it:

What	Size
Notion app data	7.7G
Google Chrome cache	7.4G
Claude desktop	6.8G
OperaGX	1.6G
VS Code	1.7G
Discord	998M
Whisky (unused)	854M
Wondershare installer	493M
TabNine models	477M
`.rustup` toolchain	1.4G
`.android` SDK	515M
`.pub-cache`	434M
`.nvm` Node versions	204M
`.npm` cache	460M

That's ~30GB in things that either don't need to be on the internal drive or can be moved transparently.

The Solution: SSD as Primary Storage via Symlinks

The core idea is simple. macOS follows symlinks transparently — apps and tools have no idea they're reading from an external drive.

# Move Downloads to SSD
mv ~/Downloads /Volumes/007/Downloads
ln -s /Volumes/007/Downloads ~/Downloads

# Now everything that writes to ~/Downloads
# actually writes to the SSD — no config changes needed

I did this for:

~/Downloads, ~/Documents, ~/Desktop, ~/Movies
All Dev projects (leadgen-platform, linkedin_automate, etc.)
Toolchains: .rustup, .cargo, .android, .nvm, .npm, .m2, .gradle, .pub-cache

Result: 36GB freed on internal. Mac went from 96% full to 68% full in one session.

The Automation Layer

Moving files manually is a one-time fix. The real value is automation. I built 27 shell scripts and wired them to macOS launchd.

`ssd` — Terminal Menu for SSD Management

  ╔═══════════════════════════════════════════════════════════════════════╗
  ║                      ◈  SSD TOOLS — 007  ◈                           ║
  ╚═══════════════════════════════════════════════════════════════════════╝

  ● SSD 007   899G free / 33G used       ● Mac Internal  36G free / 17G used

  STORAGE & SYSTEM
  ┌──────┬──────────────────────┬────────────────────────────────────────┐
  │  1   │  mount-check         │  Check SSD mount + symlink health      │
  │  2   │  cache-cleanup       │  Clear caches (Library, npm, pnpm)     │
  │  3   │  low-disk-alert      │  Check internal Mac free space         │
  │  7   │  duplicate-finder    │  Scan SSD for duplicate files          │
  │ 12   │  ssd-health          │  SSD space + fill prediction           │
  └──────┴──────────────────────┴────────────────────────────────────────┘

  DEV & CODE
  ┌──────┬──────────────────────┬────────────────────────────────────────┐
  │  5   │  dev-backup          │  Rsync active projects to backup       │
  │  9   │  git-status          │  Uncommitted changes across projects   │
  │ 20   │  env-backup          │  Backup all .env files                 │
  │ 25   │  focus-mode          │  Block distractions (25min)            │
  └──────┴──────────────────────┴────────────────────────────────────────┘

`mac` — Terminal Menu for Mac System Tools

  ╔═══════════════════════════════════════════════════════════════════════╗
  ║                    ◈  MAC TOOLS — SHRAVAN  ◈                         ║
  ╚═══════════════════════════════════════════════════════════════════════╝

  CPU 12%   Battery 100% (charged)   Uptime 2 days
  Wifi HomeNetwork   IP 192.168.1.6

  SYSTEM        APPS           MAINTENANCE      SECURITY        POWER
  system-stats  kill-hogs      clear-caches     firewall-status caffeinate
  battery-health app-usage     brew-update      open-ports      sleep-timer
  wifi-info     startup-items  run-all-agents   lock-screen     battery-saver
  processes     force-quit     large-files      ssh-keys

The 18 Scheduled LaunchAgents

These run automatically via macOS launchd — no cron, no manual triggers.

# Check what's running
launchctl list | grep shravan

Agent	Schedule	What it does
dev-backup	Nightly 11pm	Rsync projects to SSD backup, keeps 7 days
dotfiles-backup	Nightly 10:30pm	Backup .zshrc, .gitconfig, SSH config
env-backup	Nightly 10pm	Backup all .env files, keeps 14 days
cache-cleanup	Monday 9am	Clear Library/Caches, npm, pnpm
git-status	Daily 9am	Report uncommitted changes across all projects
dep-audit	Monday 10am	npm vulnerability scan
ssd-health	Daily 10am	Space usage + fill rate prediction
low-disk-alert	Every hour	Alert if Mac internal < 5GB free
ram-monitor	Every 5min	Log RAM usage
battery-logger	Daily 12pm	Log battery cycles + health

Serial Lock: SSD Only Works on My Mac

I didn't want the SSD to work if stolen. So I built a serial number lock:

#!/bin/zsh
AUTHORIZED_SERIAL="CPWY0XTG9Y"
CURRENT_SERIAL=$(system_profiler SPHardwareDataType | grep "Serial Number" | awk '{print $NF}')

if [ "$CURRENT_SERIAL" != "$AUTHORIZED_SERIAL" ]; then
  diskutil eject disk5
  osascript -e 'display alert "Unauthorized Mac. SSD ejected." as critical'
fi

This fires automatically via a WatchPaths LaunchAgent whenever the SSD mounts. Wrong Mac → instant eject.

The Install Script

The whole toolkit is packaged with a one-command installer:

git clone https://github.com/sxrxvxnn/mac-ssd-toolkit
cd mac-ssd-toolkit
./install.sh

It asks for your username, SSD volume name, and project names — then configures everything, installs LaunchAgents, and adds aliases to .zshrc.

Results

Before	After
23GB free	36GB free
Manual backups	Nightly automated
No disk monitoring	Hourly alerts
Scattered dotfiles	Nightly backup
No SSD security	Serial lock

What's Next

The repo is open source and looking for contributors. If you have ideas for new scripts — storage tools, dev workflow automation, system monitoring — open an issue or PR.

GitHub: github.com/sxrxvxnn/mac-ssd-toolkit

Ideas already in the backlog:

Git commit streak tracker
Wifi speed daily logger
Auto-organize Downloads by file type
Monthly storage trend report

If you're a Mac developer with limited internal storage, give it a try. One command and you're set up.

Built while working as a BD intern at Beagle Security, building Sonar — an Apollo-style B2B intelligence platform.

DEV Community: Shravan Omanakuttan