🔧 Environment Version Switcher Toolkit for Windows ⚙️

A comprehensive suite of PowerShell scripts to quickly switch between multiple versions of Python, CUDA, cuDNN, and Visual Studio BuildTools on your Windows machine. Each tool intelligently scans for existing installations and updates your system environment variables to prioritize the version you select.

📋 Overview

Managing multiple development environment versions can be challenging. This toolkit automates the process of discovering installations and switching between them by manipulating environment variables and PATH settings. Perfect for developers working across multiple projects with different toolchain requirements.

🎯 What's Included

1. 🐍 Python Version Switcher

• Scans multiple locations for Python installations
• Updates user PATH variable
• Works with Python Launcher (py.exe) installations
• No administrator privileges required

2. 🎮 CUDA Version Switcher

• Detects all NVIDIA CUDA Toolkit installations
• Updates CUDA_PATH system variable
• Manages system PATH for CUDA binaries
• Requires Administrator privileges

3. 🧠 cuDNN Version Switcher

• Scans C:\Program Files\NVIDIA\CUDNN for versions
• Updates system PATH for cuDNN binaries
• Requires Administrator privileges

4. 🏗️ Visual Studio BuildTools Switcher

• Finds all MSVC compiler installations (cl.exe)
• Supports VS 2019, 2022, and newer versions
• Updates cl.exe system variable and PATH
• Requires Administrator privileges

5. 🚀 Master Launcher (start.bat)

• Unified menu interface for all switchers
• Quick access to any tool
• Streamlined workflow

✅ Requirements

• 🖥️ Windows Operating System: Windows 10/11 recommended
• 🔵 PowerShell: Pre-installed on modern Windows
• 🔐 Administrator Rights: Required for CUDA, cuDNN, and VS BuildTools switchers
• 📦 At least one version installed: For each tool you want to use

🚀 Quick Start

Master Launcher (Recommended)

1. Download all files to the same directory
2. Double-click start.bat
3. Select the tool you want to use from the menu:

========================================
     Environment Version Switcher
========================================

   1. Python Version Switcher
   2. CUDA Version Switcher             (Requires Admin)
   3. cuDNN Version Switcher            (Requires Admin)
   4. VS (BuildTools) Version Switcher  (Requires Admin)

   0. Exit

========================================
Select an option [0-4]:

Individual Usage

You can also run each switcher independently by double-clicking its .bat file:

• python_switcher.bat
• cuda_switcher.bat
• cudnn_switcher.bat
• vs_buildtools_switcher.bat

📖 Detailed Usage

🐍 Python Version Switcher

Features:

• Scans %LOCALAPPDATA%\Programs\Python, %ProgramFiles%, and system directories
• Detects Python Launcher installations
• Updates user PATH (no admin needed)
• Removes duplicate entries before adding selected version

Example Output:

Found 3 Python installation(s):

1. Python 3.12.0 - C:\Users\YourUser\AppData\Local\Programs\Python\Python312
   [User Installation]
2. Python 3.11.5 - C:\Users\YourUser\AppData\Local\Programs\Python\Python311
   [User Installation]
3. Python 3.9.13 - C:\Program Files\Python39
   [System Installation]

0. Exit without changes

🎮 CUDA Version Switcher

Features:

• Detects versions via CUDA_PATH_V*_* environment variables
• Updates CUDA_PATH system variable
• Cleans old CUDA paths from system PATH
• Adds bin, libnvvp, bin\x64, and extras\CUPTI\lib64 folders
• Verifies installation with nvcc --version

Example Output:

Found 2 CUDA installation(s):

1. CUDA v13.1 - C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v13.1
2. CUDA v11.8 - C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v11.8

0. Exit without changes

Admin Required: ✅ This tool modifies system environment variables.

🧠 cuDNN Version Switcher

Features:

• Scans C:\Program Files\NVIDIA\CUDNN
• Removes old cuDNN paths from system PATH
• Adds selected version's bin folder to PATH

Example Output:

Found 2 cuDNN installation(s):

1. cuDNN v9.0.0.312_cuda12 - C:\Program Files\NVIDIA\CUDNN\v9.0.0.312_cuda12\bin
2. cuDNN v8.9.7.29_cuda11 - C:\Program Files\NVIDIA\CUDNN\v8.9.7.29_cuda11\bin

0. Exit without changes

Admin Required: ✅ This tool modifies system environment variables.

🏗️ Visual Studio BuildTools Switcher

Features:

• Scans both Program Files and Program Files (x86)
• Finds all VS editions (BuildTools, Community, Professional, Enterprise)
• Supports VS 2019, 2022, and future versions
• Sets cl.exe system variable
• Uses Hostx64\x64 for native 64-bit compilation

Example Output:

Found 2 installation(s):

1. v14.44.35207 - 2022 BuildTools
   Path: C:\Program Files\Microsoft Visual Studio\2022\BuildTools\VC\Tools\MSVC\14.44.35207\bin\Hostx64\x64
2. v14.39.33519 - 2022 Community
   Path: C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.39.33519\bin\Hostx64\x64

0. Exit without changes

Admin Required: ✅ This tool modifies system environment variables.

🔒 Administrator Privileges

Tools That Need Admin:

• ✅ CUDA Switcher - Modifies system variables
• ✅ cuDNN Switcher - Modifies system variables
• ✅ VS BuildTools Switcher - Modifies system variables

Tools That Don't Need Admin:

• ❌ Python Switcher - Only modifies user PATH

When admin is required, the .bat launcher will automatically request elevation via UAC prompt.

💡 Important Notes

Environment Variable Scopes

• Python Switcher: Modifies PATH for current user only
• CUDA/cuDNN/VS Switchers: Modify system-wide variables (all users)

Taking Effect

After switching versions:

1. Close and reopen all Command Prompts, PowerShell windows, and IDEs
2. For CUDA/VS tools: If changes don't take effect, reboot Windows
3. Current session: The script updates the current terminal for immediate testing

Safety Features

• ✅ Confirmation prompt before making changes
• ✅ Shows exactly what will be modified
• ✅ Removes old/duplicate paths to prevent conflicts
• ✅ Only adds folders that actually exist on disk
• ✅ Graceful error handling with clear messages

🛠️ Troubleshooting

"No installations found"

• Ensure the software is installed in standard locations
• For CUDA: Check if CUDA_PATH_V*_* environment variables exist
• For cuDNN: Check C:\Program Files\NVIDIA\CUDNN
• For VS: Check C:\Program Files\Microsoft Visual Studio

Changes don't take effect

1. Restart your terminal/IDE completely
2. Open a new Command Prompt or PowerShell window
3. For system variables (CUDA/VS), try rebooting Windows

"Requires Administrator privileges" error

• Right-click the .bat file
• Select "Run as administrator"
• Or use the master launcher which handles elevation automatically

PowerShell execution policy errors

• The .bat launchers use -ExecutionPolicy Bypass flag
• This bypasses policy for just that session (safe)
• No permanent system changes needed

📁 File Structure

Environment-Switcher/
├── start.bat                      # Master launcher menu
├── python_switcher.bat            # Python launcher
├── python_switcher.ps1            # Python core script
├── cuda_switcher.bat              # CUDA launcher
├── cuda_switcher.ps1              # CUDA core script
├── cudnn_switcher.bat             # cuDNN launcher
├── cudnn_switcher.ps1             # cuDNN core script
├── vs_buildtools_switcher.bat     # VS BuildTools launcher
├── vs_buildtools_switcher.ps1     # VS BuildTools core script
└── README.md                      # This file

🎨 Features Highlight

Intelligent Path Management

• Automatically removes duplicate entries
• Validates folder existence before adding to PATH
• Prioritizes selected version at the top of PATH
• Preserves other environment variables

Future-Proof Design

• Not hardcoded to specific versions
• Works with Python 3.x, CUDA 11.x/12.x/13.x+, any VS version
• Automatically adapts to new installations
• Version detection via folder scanning and registry checks

User Experience

• Color-coded console output for clarity
• Clear version numbers and paths displayed
• Numbered selection menus (no typing long paths)
• Confirmation prompts to prevent accidents
• Immediate verification of changes

⚠️ Disclaimer

These scripts modify your system's environment variables. While designed to be safe and include multiple confirmation steps, please use at your own risk. Always understand what a script does before running it with administrator privileges.

Best Practice: Test on a non-critical machine first if you're uncertain.

📝 Version History

• v2.0 - Complete toolkit with master launcher
• v1.2 - Added VS BuildTools switcher
• v1.1 - Added CUDA and cuDNN switchers
• v1.0 - Initial Python version switcher

🤝 Contributing

Found a bug or have a feature request? Feel free to open an issue or submit a pull request!

📄 License

MIT License - Feel free to use, modify, and distribute as needed.

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Made with ❤️ for developers who need to juggle multiple environment versions