How to use audio convert with terminal parameter?

I want to convert a set of flac files to aac using best resolution for aac file . I found this tool [audio convert](https://savannah.nongnu.org/projects/audio-convert) but I am missing the man page or a help side. The command works when I use audio-convert .flac but it starts some graphical choice wizard. Is there a way to only use one terminal command so I can batch it over a set files?