Suppose you want to trace multiple bitmaps with some fixed inkscape tracing settings, is there a way to do it automatically with a batch file?
Inkscape trace bitmaps with an embedded version of Potrace. Unfortunately we can not access this from the command line. In additions there are no shared libraries from Inkscape and Portrace meaning you will have to install potrace in addition to Inkscape for command line batch tracing of bitmaps.
The advantage of doing so is that you will have far more access to fine tune your traces with specific options nicely listed in the potrace manual.
On Linux systems potrace should be available from your software repositories. Source packages and precompiled binaries for other operating systems are available from sourceforge.