diff --git a/histrap.c b/histrap.c
index 320ce77..d19dbb6 100644
--- a/histrap.c
+++ b/histrap.c
@@ -27,7 +27,7 @@
 #include <sys/file.h>
 #endif
 
-__RCSID("$MirOS: src/bin/mksh/histrap.c,v 1.147 2015/07/05 19:37:15 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/histrap.c,v 1.148 2015/07/05 19:53:45 tg Exp $");
 
 Trap sigtraps[ksh_NSIG + 1];
 static struct sigaction Sigact_ign;
@@ -84,6 +84,9 @@ static const char TFCEDIT_dollaru[] = "${FCEDIT:-/bin/ed} $_";
 /* maximum considered size of persistent history file */
 #define MKSH_MAXHISTFSIZE	((off_t)1048576 * 96)
 
+/* hidden option */
+#define HIST_DISCARD		5
+
 int
 c_fc(const char **wp)
 {
@@ -567,6 +570,7 @@ sethistfile(const char *name)
 		afree(hname, APERM);
 		hname = NULL;
 		/* let's reset the history */
+		histsave(NULL, NULL, HIST_DISCARD, true);
 		histptr = history - 1;
 		hist_source->line = 0;
 	}
@@ -601,6 +605,8 @@ histsync(void)
 {
 	bool changed = false;
 
+	/* called by histsave(), may not HIST_DISCARD, caller should flush */
+
 	if (histfd != -1) {
 		int lno = hist_source->line;
 
@@ -626,6 +632,12 @@ histsave(int *lnp, const char *cmd, int svmode, bool ignoredups)
 	char **hp, *c;
 	const char *ccp;
 
+	if (svmode == HIST_DISCARD) {
+		afree(enqueued, APERM);
+		enqueued = NULL;
+		return;
+	}
+
 	if (svmode == HIST_APPEND) {
 		if (!enqueued)
 			svmode = HIST_STORE;
@@ -734,6 +746,8 @@ hist_init(Source *s)
 	enum { hist_init_first, hist_init_retry, hist_init_restore } hs;
 #endif
 
+	histsave(NULL, NULL, HIST_DISCARD, true);
+
 	if (Flag(FTALKING) == 0)
 		return;
 
diff --git a/lex.c b/lex.c
index 7839d90..fb80244 100644
--- a/lex.c
+++ b/lex.c
@@ -23,7 +23,7 @@
 
 #include "sh.h"
 
-__RCSID("$MirOS: src/bin/mksh/lex.c,v 1.203 2015/07/05 19:37:16 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/lex.c,v 1.204 2015/07/05 19:53:46 tg Exp $");
 
 /*
  * states while lexing word
@@ -1474,8 +1474,10 @@ getsc_line(Source *s)
 		cp = Xstring(s->xs, xp);
 		while (*cp && ctype(*cp, C_IFSWS))
 			++cp;
-		if (!*cp)
+		if (!*cp) {
+			histsave(&s->line, NULL, HIST_FLUSH, true);
 			histsync();
+		}
 #endif
 	}
 	if (interactive)