Command Line Sound File Mixer

The overall purpose is to have a command line application take a set of input sound files (.wav/.mp3 and mono/stereo) each with it's own unique starting time frame and filter/volume normalize/mix them into a single output file (.wav or .mp3). This application will be used as a sub-component within several other larger applications. I need a command line application to take as input several text files which contain: A) parameters for the mixing operation - [login to view URL] B) list of files to be mixed together with millisecond timing for each - [login to view URL] If an existing FOSS (Free Open Source Software) application can be leveraged via either a batch file, a script (audacity?) or API, that would be ideal and not require all the functionality be re-programmed. This application is intended to be a very simple idea, something that can easily be done manually via a GUI in many applications. However, do to what I am creating, using a GUI does not meet my need as I will be having another "system" executing this component to generate results and then automatedly transport them elsewhere.