Recent builds from git will bring you a new executable, “darktable-cli”. With this tool you can export images using the processing power of darktable on the command line.
The simplest way to call the utility is
darktable-cli This will take the input image, look for the XMP file associated with it, process it at maximal resolution and write the output to output, trying to guess the output format from the output filename. You can also explicitly give a XMP file by running
This is a companion discussion topic for the original entry at https://www.darktable.org/2012/07/exporting-images-on-the-command-line/