I am looking for a program that can merge many MP3 files via command line on Ubuntu (e.g., as soon I have a folder containing many MP3 files and I want to merge them into a single MP3 file).
mp3wrapmay only merge up to 255 files (http://mp3wrap.sourceforge.net/faq.html#q6 (mirror))
soxmay only merge up to 348 files (https://superuser.com/a/571468/116475 (mirror)). I'm not sure if the 348 but whatever the exact number is, there seems to be a low limit in the hundreds of thousands.
Any license or price is fine.