Gas Mask

Gas Mask is a simple and user-friendly macOS system hosts file manager. It allows users to easily edit hosts files and quickly switch between different configurations, serving as a powerful tool for developers and system administrators to optimize network connections, block ads, or conduct local testing.

Features

1. Visual Hosts File Management

• Provides a clear main editor window with a list of hosts files on the left and an editing area on the right.
• Supports creating local files, remote files (from URLs), or combined files.
• Automatically backs up your original system hosts file on first launch for easy restoration.

2. Instant Switching and Activation

• Activate or switch to any hosts configuration with one click via the menu bar icon or main interface.
• The selected configuration is instantly applied to the system /etc/hosts file without manual replacement.

3. Multi-type File Support

• Local Files: Create and edit directly within the app.
• Remote Files: Load and update hosts rules from network URLs (e.g., popular ad-blocking lists).
• Combined Files: Merge contents of local and remote files into a single configuration.

4. System Integration & Security

• Requires administrator privileges only once at first launch, for securely modifying the /etc/hosts system file.
• All custom hosts files are stored under the user directory ~/Library/Gas Mask, isolated from system files for clear management.

Key Advantages

✅ User-friendly and Efficient

• Eliminates the need for command-line operations or tedious file replacements. All hosts management tasks are completed through a graphical interface—switching rules is as simple as a single click, greatly improving development and testing efficiency.

✅ Flexible Configuration and Powerful Combination

• Supports mixing local rules with remote subscription lists (e.g., blocking ads, malicious websites), enabling highly flexible and robust network environment setups.

✅ Secure and Easy to Recover

• Always retains a backup of the original hosts file, allowing effortless rollback in case of errors and preventing irreversible network issues.
• Detailed logging (~/Library/Logs/Gas Mask.log) for easy troubleshooting.

✅ Lightweight Background Operation

• Runs as a menu bar icon, occupying no main screen space. Accessible anytime without interfering with normal workflow.

System Requirements: Compatible with macOS Lion (10.7) through Mojave (10.14) and later versions.

In summary, Gas Mask transforms the traditionally terminal-based hosts file management into an intuitive, secure, graphical process. Whether for development debugging, privacy protection, or network optimization, it is an essential and indispensable utility.