diff --git a/C/scanner.c b/C/scanner.c
index aa564d0f3..77cb8d6eb 100755
--- a/C/scanner.c
+++ b/C/scanner.c
@@ -315,6 +315,11 @@ read_quoted_char(int *scan_nextp, IOSTREAM *inp_stream)
     return '\n';
   case 'r':
     return '\r';
+  case 's':         /* space */
+    if (yap_flags[CHARACTER_ESCAPE_FLAG] == ISO_CHARACTER_ESCAPES) {
+      return send_error_message("invalid escape sequence \\s");
+    } else
+      return ' ';
   case 't':
     return '\t';
   case 'u':
@@ -357,6 +362,11 @@ read_quoted_char(int *scan_nextp, IOSTREAM *inp_stream)
     }
   case 'v':
     return '\v';
+  case 'z':         /* Prolog end-of-file */
+    if (yap_flags[CHARACTER_ESCAPE_FLAG] == ISO_CHARACTER_ESCAPES) {
+      return send_error_message("invalid escape sequence \\z");
+    } else
+      return -1;
   case '\\':
     return '\\';
   case '\'':
diff --git a/pl/boot.yap b/pl/boot.yap
index 28019513f..12423bb03 100755
--- a/pl/boot.yap
+++ b/pl/boot.yap
@@ -144,18 +144,18 @@ true :- true.
 */
 
 /* main execution loop							*/
-'$read_vars'(user_input, Goal, Mod, Pos, Bindings) :-
+'$read_vars'(user_input, Goal, Mod, Pos, Bindings, Prompt) :-
 	'$swi_current_prolog_flag'(readline, true),
 	read_history(h, '!h',
                          [trace, end_of_file],
-                         ' ?- ', Goal, Bindings), !,
+                         Prompt, Goal, Bindings), !,
 	(nonvar(Err) ->
 	 print_message(error,Err), fail
 	;
 	 true
 	).
-'$read_vars'(Stream,T,Mod,Pos,V) :-
-	'$read'(true,T,Mod,V,Pos,Err,Stream),
+'$read_vars'(Stream, T, Mod, Pos, V, _Prompt) :-
+	'$read'(true, T, Mod, V, Pos, Err, Stream),
 	(nonvar(Err) ->
 	 print_message(error,Err), fail
 	;
@@ -195,13 +195,12 @@ true :- true.
 	prompt(_,'| '),
 	prompt1(' ?- '),
 	'$run_toplevel_hooks',
-	'$read_vars'(user_input,Command,_,Pos,Varnames),
+	'$read_vars'(user_input,Command,_,Pos,Varnames, ' ?- '),
 	nb_setval('$spy_gn',1),
-		% stop at spy-points if debugging is on.
-
+				% stop at spy-points if debugging is on.
 	nb_setval('$debug_run',off),
 	nb_setval('$debug_jump',off),
-	prompt(_,'|: '),
+	prompt1('|: '),
 	'$command'(Command,Varnames,Pos,top),
 	'$sync_mmapped_arrays',
 	set_value('$live','$false').
@@ -1141,7 +1140,7 @@ bootstrap(F) :-
 	!.
 
 '$enter_command'(Stream,Status) :-
-	'$read_vars'(Stream,Command,_,Pos,Vars),
+	'$read_vars'(Stream,Command,_,Pos,Vars, '|: '),
 	'$command'(Command,Vars,Pos,Status).
 
 '$abort_loop'(Stream) :-
diff --git a/pl/flags.yap b/pl/flags.yap
index 0982737e8..2b7fc457d 100644
--- a/pl/flags.yap
+++ b/pl/flags.yap
@@ -958,7 +958,7 @@ yap_flag(dialect,yap).
 '$yap_flag_show_gc_tracing'(_, _, _, off).
 
 '$flag_check_alias'(OUT, Alias) :-
-	stream_property(OUT,[alias(Alias)]), !.
+	stream_property(OUT,alias(Alias)), !.
 	
 current_prolog_flag(V,Out) :-
 	var(V), !,