Comment 2 for bug 843260

As mentioned in the manual page, the option to suppress the GUI is intended to work only in combination with a limited number of other options:

  -z, --without-gui
          Do not open the GUI (on Unix, do not use X server); only
          process the files from console. This is assumed for -p, -e,
          -l, and --vacuum-defs options.

The usage of verbs on the command line has several known limitations. Other related reports are:
Bug #168616: running FileSave verb from command line doesn't work
Bug #361237: Provide scriptable method of saving files
Bug #626854: --verb actions not possible in --shell mode

Usually I refer users to bug #168616 when the question how to use verbs without GUI comes up, but report #168616 actually describes two (AFAIU unrelated) issues (FitCanvasToDrawing doesn't 'dirty' the file, '-z' doesn't work with verbs). Maybe we should keep this one as separate feature request to support (certain) verbs from the command line without opening the GUI?