import re


def update_server_property(file_path, property_name, new_value):
    """
    Updates a specified property in a Minecraft server configuration file.

    Parameters:
    - file_path: Path to the Minecraft server configuration file.
    - property_name: Name of the property to update.
    - new_value: New value to set for the property.
    """
    # Regular expression pattern to match lines containing the property name
    pattern = rf'^{property_name}=.*$'

    # Read the file content
    with open(file_path, 'r') as file:
        content = file.readlines()

    # Find the line containing the property and update its value
    for i, line in enumerate(content):
        if re.match(pattern, line):
            content[i] = f"{property_name}={new_value}\n"
            break
    else:
        raise ValueError(f"Property '{property_name}' not found in the file.")

    # Write the updated content back to the file
    with open(file_path, 'w') as file:
        file.writelines(content)

# Example usage
file_path = 'folder/server.properties'
property_name = 'server-ip'
new_value = '127.0.0.1'
update_server_property(file_path, property_name, new_value)