Free Mac Monitor

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English

A minimal macOS menu-bar system monitor with a retro CRT / Pip-Boy aesthetic. Pure Swift + AppKit + WebKit, zero third-party dependencies.

Download & install

Prebuilt universal binary (Apple Silicon + Intel, ad-hoc signed — not notarised):

Method	Command
One-line install	curl -fsSL https://raw.githubusercontent.com/pekinlcc/FreeMacMonitor/main/scripts/install.sh | bash
Manual	Download the latest release, unzip, then drag Free Mac Monitor.app into /Applications.

Because the app is not signed with an Apple Developer certificate, Gatekeeper will refuse to open it on first launch. Choose one:

• Recommended — run xattr -cr "/Applications/Free Mac Monitor.app" in Terminal to strip the quarantine flag, then open normally. The installer script already does this for you.
• In Finder, right-click the app and choose Open → Open in the dialog.
• Or go to System Settings → Privacy & Security, scroll to the blocked-app notice and click Open Anyway.

If you prefer building from source, see Build & run below.

Screenshots

  

Liquid Glass (default) · Fallout Terminal

Right-click menu

Features

• Two themes (v1.2) — a Liquid Glass look (translucent NSVisualEffectView-backed popover, SF Pro typography, gradient pill bars) by default, and a Fallout Terminal look (VT323 CRT phosphor green, ASCII bars, scanlines). Switch via right-click → Theme ▸; both layouts share the same DOM and state.
• Menu-bar indicator — a small >> icon that turns red when any metric breaches its alert threshold.
• Live-metrics mode (v1.0) — right-click the icon and toggle Show Live Metrics. The icon becomes a rolling readout that cycles every 3 seconds through:

  CPU 20%  →  MEM 64%  →  GPU  5%  →  DSK 59%
  

  When a threshold is breached the rotation locks onto the offending metric and turns red, so you see the problem within one cycle.
• Expanding panel — left-click to open a 320 × 460 dashboard with live bar charts. Click anywhere outside to collapse.
• Memory breakdown (v1.1) — toggle Show Memory Breakdown and the memory bar becomes a 5-colour stacked chart (App / Wired / Compressed / Cached / Free), matching Activity Monitor's categories. Legend renders as a 5-row grid with GB values per category, never wraps.
• Auto-release at high pressure (v1.1) — when (App + Wired + Compressed) / Total ≥ 98 % for 3 consecutive seconds, optionally fire /usr/sbin/purge and show a live status-bar animation ([FLUSH ▓▓▓▓] → MEM 82% ▼16) with the real measured reduction. Auto modes (right-click → Auto-Release Memory): Notify only / Auto-run with a pre-set sudoers rule / Off. The password-prompt purge is manual-only — it needs an explicit user action, so it never pops an admin dialog from the background. ⌘R from the menu triggers a one-shot release manually.
• Adaptive polling (v1.3) — 1 Hz while the panel is open or Live Metrics is on; relaxed to 0.2 Hz (with GPU/disk sampled even less often) when only the alert thresholds need watching. Timer tolerance lets macOS coalesce wakeups, so the monitor itself stays near-zero cost.
• Configurable alert thresholds (v1.4) — right-click → Alert Thresholds ▸ to pick the per-metric percentage that turns the icon red (defaults: CPU/MEM/GPU 80 %, Disk 85 %).
• Launch at Login (v1.4) — one menu toggle, implemented with SMAppService (no helper app, no LaunchAgent plist).
• Update notifications (v1.4) — checks GitHub Releases once a day (and on demand via Check for Updates…); click the notification to open the release page. No Sparkle, no telemetry — one anonymous API call.
• Fully offline panel (v1.4) — the VT323 terminal font is bundled (OFL licence included) instead of loaded from Google Fonts, so the Fallout theme renders identically with no network and no font request.
• Persistent preferences — theme, Show Live Metrics, Show Memory Breakdown, Auto-Release mode, and alert thresholds all stored in UserDefaults.

Requirements

• macOS 13 Ventura or later
• Swift 5.9+ (ships with Xcode 15 / Command Line Tools)

Build & run

./build.sh
open "Free Mac Monitor.app"

If Gatekeeper blocks the unsigned build:

xattr -cr "Free Mac Monitor.app" && open "Free Mac Monitor.app"

Right-click menu

Item	Action
Show Live Metrics	Toggles the rotating readout in the menu bar.
Show Memory Breakdown	Switches the MEMORY row to a 5-colour stacked chart + legend.
Theme ▸	Sub-menu: Liquid Glass (default) · Fallout Terminal.
Auto-Release Memory ▸	Sub-menu: Notify only · Auto-run sudoers-free · Off.
Release Memory Now… ⌘R	One-shot manual purge (prompts for password unless sudoers is set up).
Alert Thresholds ▸	Per-metric red-alert percentage (CPU / Memory / GPU / Disk).
Launch at Login	Registers/unregisters the app as a login item via SMAppService.
Check for Updates…	Queries GitHub Releases and notifies you of the result.
Quit Free Mac Monitor	Exits the app.

Left-click opens / closes the dashboard panel.

Auto-release modes

/usr/sbin/purge is the only honest mechanism macOS offers for explicit memory release — typically it frees 0.2–1 GB of disk cache — and it requires root. The auto modes trade off between friction and automation:

1. Notify only (default) — On sustained 98 % pressure the app posts a macOS notification. You stay in control; no command runs automatically.

2. Auto-run — sudoers-free — The app runs sudo -n /usr/sbin/purge. This requires a one-time sudoers rule so that no password is needed:

   # Run once; replace $USER with your login
   echo "$USER ALL=(root) NOPASSWD: /usr/sbin/purge" \
       | sudo tee /etc/sudoers.d/free-mac-monitor-purge > /dev/null
   sudo chmod 440 /etc/sudoers.d/free-mac-monitor-purge

3. Off — nothing happens automatically.

The password-prompt purge (osascript … with administrator privileges) is manual-only: it is used for Release Memory Now…, never from the background, because an automatic trigger raising a credential dialog is disruptive and can loop under pressure. Manual triggers are one-shot regardless of the selected auto mode.

Cooldown between triggers is 60 seconds; the status-bar animation shows the measured drop (▼N). The delta measures the change in total used (App + Wired + Compressed + Cached) — purge frees file-backed cache, so measuring only the pressure buckets would always show ▼0 even after freeing gigabytes. If nothing actually got released, the app honestly displays ▼0.

Alert thresholds

Configurable via right-click → Alert Thresholds ▸ (stored in UserDefaults):

Metric	Default	Choices
CPU	80%	60 / 70 / 80 / 90
Memory	80%	60 / 70 / 80 / 90
GPU	80%	60 / 70 / 80 / 90
Disk	85%	70 / 80 / 85 / 90 / 95

Regenerating the app icon

The icon is produced by a tiny Core Graphics script:

swift scripts/make_icon.swift AppIcon.iconset
iconutil -c icns AppIcon.iconset
rm -rf AppIcon.iconset

Output: AppIcon.icns at the project root, which build.sh copies into the bundle.

Project layout

Sources/FreeMacMonitor/
  main.swift                — NSApplication bootstrap (accessory activation policy)
  AppDelegate.swift         — wires up the status bar controller
  StatusBarController.swift — status item, panel, polling, rotation + alert logic
  SystemMetrics.swift       — CPU / memory / GPU / disk sampling via Darwin + IOKit
  Resources/
    index.html / app.js / style.css — Pip-Boy dashboard UI
scripts/
  make_icon.swift           — Core Graphics icon generator
build.sh                    — SPM release build + .app assembly
Info.plist                  — LSUIElement, CFBundleIconFile, identifiers

How it works

• The app runs with LSUIElement = true — no Dock icon, no app-switcher entry.
• A single adaptive timer (1 Hz watched / 0.2 Hz idle, with tolerance for wakeup coalescing) drives both the menu-bar render and the (optional) WebKit panel update. The Mach host port, page size, and total RAM are cached once; GPU utilisation is read via a single-key IORegistryEntryCreateCFProperty fetch and disk via one cached statfs — the sampling hot path allocates almost nothing.
• The dashboard is local HTML (loaded via WKWebView.loadFileURL) and receives metric updates through evaluateJavaScript calls — simple, no IPC, no server.
• Clicking outside the open panel is caught with NSEvent.addGlobalMonitorForEvents, which fires only for events in other apps' windows, avoiding re-toggle races with the status-bar button click.

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中文

极简的 macOS 菜单栏系统监视器，采用复古 CRT / Pip-Boy 风格。纯 Swift + AppKit + WebKit 实现，零第三方依赖。

下载与安装

预编译通用二进制（Apple Silicon + Intel，使用 ad-hoc 签名 —— 未经 Apple 公证）：

方式	命令
一行命令安装	curl -fsSL https://raw.githubusercontent.com/pekinlcc/FreeMacMonitor/main/scripts/install.sh | bash
手动下载	前往 Releases 页面 下载压缩包，解压后把 Free Mac Monitor.app 拖到 /Applications。

由于应用没有使用 Apple Developer 证书签名，首次启动时 Gatekeeper 会拒绝打开。任选其一：

• 推荐 —— 在 Terminal 中执行 xattr -cr "/Applications/Free Mac Monitor.app" 去除隔离标记，然后正常打开。一键安装脚本已经帮你做了这一步。
• 在 Finder 中右键应用，选择 打开 → 在弹窗中再次点击 打开。
• 或前往 系统设置 → 隐私与安全性，滚动到被拦截的应用提示处，点击 仍要打开。

如果你更倾向于从源码编译，请看下方 编译与运行。

截图

  

Liquid Glass（默认） · Fallout Terminal

右键菜单

功能特性

• 双主题 （v1.2） —— 默认 Liquid Glass 液态玻璃外观（半透明 NSVisualEffectView 背板 + SF Pro + 渐变 pill 柱状图）；也可切换到 Fallout Terminal（VT323 荧光绿 CRT + ASCII 柱状图 + 扫描线）。右键 → Theme ▸ 切换，两套皮肤共用 DOM 和状态。
• 菜单栏指示器 —— 一个小小的 >> 图标，当任何指标突破预警阈值时会变红。
• 实时指标模式 （v1.0） —— 右键点击图标，切换 Show Live Metrics。图标会变成滚动读数，每 3 秒循环显示：

  CPU 20%  →  MEM 64%  →  GPU  5%  →  DSK 59%
  

  当某项指标触发阈值时，滚动会锁定在该指标并显示为红色，一个循环内就能看到问题。
• 展开面板 —— 左键点击可打开 320 × 460 仪表盘，内含实时柱状图。点击外部任意位置即可收起。
• 内存分类展示 （v1.1） —— 勾选 Show Memory Breakdown 后，内存柱会变成 5 色 stacked 条（App / Wired / Compressed / Cached / Free），与 Activity Monitor 的分类一致。图例以 5 行栅格呈现，每行"色块 · 名称 · GB 数值"，永不换行。
• 高压自动清理 （v1.1） —— 当 (App + Wired + Compressed) / 总内存 ≥ 98 % 持续 3 秒时，可选地调用 /usr/sbin/purge 并在菜单栏播放动画（[FLUSH ▓▓▓▓] → MEM 82% ▼16），▼N 是实测下降百分点。自动模式（右键 → Auto-Release Memory）：仅通知 / 自动运行（免密码 sudoers）/ 关闭。弹密码的清理只用于手动触发——密码框必须由用户显式动作发起，后台绝不会自动弹窗。⌘R 立即手动触发一次清理。
• 自适应轮询 （v1.3） —— 面板打开或开启实时指标时 1 Hz 采样；仅需检查告警阈值时降到 0.2 Hz（GPU / 磁盘采样频率更低），并设置 timer tolerance 让系统合并唤醒 —— 监控工具本身几乎不耗电。
• 可配置告警阈值 （v1.4） —— 右键 → Alert Thresholds ▸ 按指标选择变红阈值（默认 CPU/内存/GPU 80 %，磁盘 85 %）。
• 登录自启动 （v1.4） —— 菜单一键开关，基于 SMAppService 实现（无 helper、无 LaunchAgent plist）。
• 更新提醒 （v1.4） —— 每天检查一次 GitHub Releases（也可通过 Check for Updates… 手动检查），点击通知直达发布页。无 Sparkle、无遥测，只有一次匿名 API 请求。
• 面板完全离线 （v1.4） —— VT323 终端字体已随应用打包（附 OFL 许可证），不再从 Google Fonts 加载；Fallout 主题在无网络时渲染效果完全一致。
• 偏好持久化 —— 主题、实时指标、内存分类、自动清理模式、告警阈值全部存储在 UserDefaults。

系统要求

• macOS 13 Ventura 或更高版本
• Swift 5.9+（随 Xcode 15 / Command Line Tools 一并提供）

编译与运行

./build.sh
open "Free Mac Monitor.app"

如果 Gatekeeper 阻止了未签名的应用：

xattr -cr "Free Mac Monitor.app" && open "Free Mac Monitor.app"

右键菜单

菜单项	功能
Show Live Metrics	切换菜单栏中的滚动读数显示。
Show Memory Breakdown	将 MEMORY 行切换为 5 色 stacked 柱 + 图例。
Theme ▸	子菜单：Liquid Glass（默认） · Fallout Terminal。
Auto-Release Memory ▸	子菜单：仅通知 · 自动运行免密码 · 关闭。
Release Memory Now… ⌘R	立即手动跑一次 purge（未配置 sudoers 免密码则弹管理员密码）。
Alert Thresholds ▸	按指标设置变红的告警阈值（CPU / 内存 / GPU / 磁盘）。
Launch at Login	通过 SMAppService 注册 / 取消登录自启动。
Check for Updates…	查询 GitHub Releases 并以通知告知结果。
Quit Free Mac Monitor	退出应用。

左键点击可展开 / 收起仪表盘面板。

自动清理模式

macOS 上唯一诚实的显式内存释放机制是 /usr/sbin/purge（通常释放 0.2–1 GB 的磁盘缓存），它需要 root 权限。自动模式在易用性和自动化程度之间做取舍：

1. 仅通知（默认）—— 98% 持续压力时只发送 macOS 原生通知，不会自动执行任何命令。

2. 自动运行（免密码 sudoers） —— 通过 sudo -n /usr/sbin/purge 触发。需要一次性配置 sudoers 规则：

   # 只需执行一次；把 $USER 替换成你的登录名
   echo "$USER ALL=(root) NOPASSWD: /usr/sbin/purge" \
       | sudo tee /etc/sudoers.d/free-mac-monitor-purge > /dev/null
   sudo chmod 440 /etc/sudoers.d/free-mac-monitor-purge

3. 关闭 —— 不自动执行任何操作。

弹密码的 purge（osascript … with administrator privileges）仅限手动：只有 Release Memory Now… 会用到它，后台自动触发绝不弹凭据框——后台反复弹密码既打扰人又可能在高压下形成循环。手动触发不受所选自动模式限制，随时可用。

触发之间有 60 秒冷却，状态栏动画里的 ▼N 是实测下降百分点。下降量按总占用（App + Wired + Compressed + Cached）的前后差值计算——purge 释放的是文件缓存（Cached），若只按压力桶计算，即使释放了几个 GB 也会显示 ▼0。实际没释放出来就显示 ▼0，不会造假。

预警阈值

通过右键 → Alert Thresholds ▸ 配置（保存在 UserDefaults）：

指标	默认值	可选值
CPU	80%	60 / 70 / 80 / 90
内存	80%	60 / 70 / 80 / 90
GPU	80%	60 / 70 / 80 / 90
磁盘	85%	70 / 80 / 85 / 90 / 95

重新生成应用图标

图标由一个小型 Core Graphics 脚本生成：

swift scripts/make_icon.swift AppIcon.iconset
iconutil -c icns AppIcon.iconset
rm -rf AppIcon.iconset

输出：位于项目根目录的 AppIcon.icns，build.sh 会把它复制到应用包中。

项目结构

Sources/FreeMacMonitor/
  main.swift                — NSApplication 引导（accessory 激活策略）
  AppDelegate.swift         — 装配状态栏控制器
  StatusBarController.swift — 状态项、面板、轮询、滚动与阈值逻辑
  SystemMetrics.swift       — 通过 Darwin + IOKit 采样 CPU / 内存 / GPU / 磁盘
  Resources/
    index.html / app.js / style.css — Pip-Boy 仪表盘 UI
scripts/
  make_icon.swift           — Core Graphics 图标生成脚本
build.sh                    — SPM release 编译 + .app 组装
Info.plist                  — LSUIElement、CFBundleIconFile、标识符

实现原理

• 应用以 LSUIElement = true 运行 —— 无 Dock 图标，也不出现在应用切换器中。
• 单个自适应定时器（有人看时 1 Hz，空闲 0.2 Hz，带 tolerance 供系统合并唤醒）同时驱动菜单栏渲染和（可选的）WebKit 面板更新。Mach host 端口、页大小、总内存只取一次；GPU 利用率改用单键 IORegistryEntryCreateCFProperty 读取，磁盘用带缓存的一次 statfs —— 采样热路径几乎零分配。
• 仪表盘是本地 HTML（通过 WKWebView.loadFileURL 加载），指标更新通过 evaluateJavaScript 调用发送 —— 简单直接，不需要 IPC，也不需要服务器。
• 通过 NSEvent.addGlobalMonitorForEvents 捕获面板外的点击事件，它只会在其他应用的窗口中触发，避免了与状态栏按钮点击之间的重复切换竞态。

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Font credit: the Fallout theme uses VT323 by Peter Hull, bundled under the SIL Open Font License. / Fallout 主题使用 Peter Hull 设计的 VT323 字体，按 SIL 开源字体许可证 随应用分发。