src/Doc/System/Sessions.thy

     -g NAME      select session group NAME
     -j INT       maximum number of parallel jobs (default 1)
     -l NAME      additional base logic
     -n           no build -- take existing build databases
     -o OPTION    override Isabelle system OPTION (via NAME=VAL or NAME)
-    -u OPT       override "update" option: shortcut for "-o update_OPT"
+    -u OPT       override "update" option for selected sessions
     -v           verbose
     -x NAME      exclude session NAME and all descendants
 
   Update theory sources based on PIDE markup produced by "isabelle build".\<close>}