Calibre Interactive preferences and all other options set in the GUI can be saved to a runset file.
The runset file can be loaded while invoking the gui or with an environment variable.
The following is an example of each method:
From command line:
calibre -gui -drc -runset <runset>
Set with environment variable (for DRC):
setenv MGC_CALIBRE_DRC_RUNSET_FILE /user/me/calibre/prefs/runset.drc
For more information about Calibre Interactive runsets see "About Runsets" in the Calibre Interactive and Calibre RVE User's manual.