feat: make install.sh curl-pipeable with non-interactive support

[Copilot]

Problem

The existing install.sh script required interactive user confirmation, making it incompatible with the common curl script | sh installation pattern that many users expect for quick setup.

Solution

Added comprehensive non-interactive support while preserving all existing functionality and safety checks:

Auto-Detection

The script now automatically detects when it's being run via pipe (when stdin is not a terminal) and skips the confirmation prompt:

# Now works seamlessly
curl -fsSL https://raw.githubusercontent.com/tr1xem/flux/main/install.sh | sh

Multiple Non-Interactive Options

• Command line flags: --yes, --force, --non-interactive
• Environment variable: FLUX_AUTO_INSTALL=1
• Help system: --help flag with usage information

Usage Examples

# Direct curl installation (the main requested feature)
curl -fsSL https://raw.githubusercontent.com/tr1xem/flux/main/install.sh | sh

# Explicit non-interactive flag
./install.sh --yes

# Environment variable for automation
FLUX_AUTO_INSTALL=1 ./install.sh

# Help and usage information
./install.sh --help

Implementation Details

• Minimal changes: Only 43 lines added to maintain simplicity
• Backwards compatible: Existing interactive mode unchanged
• Smart detection: Uses [[ ! -t 0 ]] to detect piped input
• Safe: All existing safety checks preserved (OS detection, root user check, etc.)
• Comprehensive: Multiple methods for different use cases

Documentation

Updated README with installation section showing all available methods and options, making it clear how users can quickly install Flux with a single command.

The script now intelligently adapts to its execution context while maintaining all security and functionality requirements.

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💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.