Is it possible to start a separate, independent instance of LO which has no interaction with an already-running LO process?
Doing so is, I think, necessary to fix a forever-standing bug in the linux unoconv batch-convertion script. unoconv works by sending commands through a socket to a separate LO process. If it can’t connect to an existing LO process for some reason, it tries to start it’s own LO process.
But when it starts its own, the LO process it starts immediately exits (with zero status) without doing anything if another LO process is running. This causes unoconv to abort.
Here is what unoconv runs to start its “own” instance:
/usr/lib/libreoffice/program/soffice.bin --headless --invisible --nocrashreport --nodefault --nofirststartwizard --nologo --norestore --accept='socket,host=127.0.0.1,port=2002,tcpNoDelay=1;urp;StarOffice.ComponentContext'
If you run this interactively with no previous LO process running, it just sits there as you might expect (doing nothing but listening on the indicated socket/port).
But if you first open a spreadsheet with
localc /path/to/something.xlsx and then run the above command in another terminal, the supposedly-second LO process exits immediately, i.e. it does not stick around and listen. Even if you specify a different port number in the --accept string.
Side note: There remains a question as to why the existing interactive LO process can not work with batch unoconv commands. I don’t know the answer. It seems to work sometimes, but often fails immediately after LO has freshly started and opened a spreadsheet interactively (as if by default there is no listener, which might be the case). Anyway, I don’t think this should matter if unoconv can reliably start its own, independent instance of LO.