src/Pure/Tools/build.scala

     Command_Line.tool {
       def show_settings(): String =
         cat_lines(List(
           "ISABELLE_BUILD_OPTIONS=" +
             quote(Isabelle_System.getenv("ISABELLE_BUILD_OPTIONS")),
-          "",
           "ISABELLE_BUILD_JAVA_OPTIONS=" +
-            quote(Isabelle_System.getenv("ISABELLE_BUILD_JAVA_OPTIONS")) +
+            quote(Isabelle_System.getenv("ISABELLE_BUILD_JAVA_OPTIONS")),
           "",
           "ML_PLATFORM=" + quote(Isabelle_System.getenv("ML_PLATFORM")),
           "ML_HOME=" + quote(Isabelle_System.getenv("ML_HOME")),
           "ML_SYSTEM=" + quote(Isabelle_System.getenv("ML_SYSTEM")),
           "ML_OPTIONS=" + quote(Isabelle_System.getenv("ML_OPTIONS"))))

     -o OPTION    override Isabelle system OPTION (via NAME=VAL or NAME)
     -s           system build mode: produce output in ISABELLE_HOME
     -v           verbose
     -x NAME      exclude session NAME and all descendants
 
-  Build and manage Isabelle sessions, depending on implicit
+  Build and manage Isabelle sessions, depending on implicit settings:
+
 """ + Library.prefix_lines("  ", show_settings()),
         "D:" -> (arg => select_dirs = select_dirs ::: List(Path.explode(arg))),
         "R" -> (_ => requirements = true),
         "X:" -> (arg => exclude_session_groups = exclude_session_groups ::: List(arg)),
         "a" -> (_ => all_sessions = true),

 
       if (verbose) {
         progress.echo(
           Library.trim_line(
             Isabelle_System.bash(
-              """echo "Started at $(date) ($ML_IDENTIFIER on $(hostname))" """).out))
-        progress.echo(show_settings())
+              """echo "Started at $(date) ($ML_IDENTIFIER on $(hostname))" """).out) + "\n")
+        progress.echo(show_settings() + "\n")
       }
 
       val start_time = Time.now()
       val results =
         progress.interrupt_handler {

             check_keywords, no_build, system_mode, verbose, exclude_sessions, sessions)
         }
       val elapsed_time = Time.now() - start_time
 
       if (verbose) {
-        progress.echo(
+        progress.echo("\n" +
           Library.trim_line(
-            Isabelle_System.bash("""echo "Finished at "; date""").out))
+            Isabelle_System.bash("""echo -n "Finished at "; date""").out))
       }
 
       val total_timing =
         (Timing.zero /: results.sessions.iterator.map(a => results(a).timing))(_ + _).
           copy(elapsed = elapsed_time)