nextcloud-desktop/doc/options.rst

ownCloud Client supports the following command line switches:

--logwindow

open a window to show log output.

--logfile <filename>

write log output to file <filename>.

--logdir <name>

write each sync log output in a new file in directory <name>

--logexpire <hours>

removes logs older than <hours> hours. (to be used with --logdir)

--logflush

flush the log file after every write.

--monoicons

Use black/white pictograms for systray.

--confdir <dirname>

Use the given configuration directory.