diff -r 0a7c43c56092 -r 1a4ed2eb48f3 doc-src/System/misc.tex
--- a/doc-src/System/misc.tex	Mon Aug 16 22:08:23 1999 +0200
+++ b/doc-src/System/misc.tex	Tue Aug 17 11:51:12 1999 +0200
@@ -223,6 +223,7 @@
     -b           build mode (output heap image, using current dir)
     -i BOOL      generate theory browsing information,
                  i.e. HTML / graph data (default false)
+    -m BOOL      multi line output (default false)
     -r           reset session path
     -s NAME      override session NAME
 
@@ -268,6 +269,11 @@
 Thus user sessions may easily link to existing Isabelle libraries already
 present on the WWW.
 
+\medskip Option \texttt{-m} controls multi-line mode of messages output as
+\texttt{usedir} proceeds.  By default, start and end of operation are printed
+on a single line.  One may specify \texttt{-m true} in case that printing of
+partial lines causes any problems, e.g.\ when doing parallel make.
+
 \medskip Any \texttt{usedir} session is named by some \emph{session
   identifier}. These accumulate, documenting the way sessions depend
 on others. For example, consider \texttt{Pure/FOL/ex}, which refers to