Index: head/sys/dev/vt/vt.h
===================================================================
--- head/sys/dev/vt/vt.h
+++ head/sys/dev/vt/vt.h
@@ -231,6 +231,7 @@
 void vtbuf_dirty(struct vt_buf *vb, const term_rect_t *area);
 void vtbuf_undirty(struct vt_buf *, term_rect_t *);
 void vtbuf_sethistory_size(struct vt_buf *, unsigned int);
+void vtbuf_clearhistory(struct vt_buf *);
 int vtbuf_iscursor(const struct vt_buf *vb, int row, int col);
 void vtbuf_cursor_visibility(struct vt_buf *, int);
 #ifndef SC_NO_CUTPASTE
Index: head/sys/dev/vt/vt_buf.c
===================================================================
--- head/sys/dev/vt/vt_buf.c
+++ head/sys/dev/vt/vt_buf.c
@@ -416,13 +416,26 @@
 		vb->vb_rows[r] = &vb->vb_buffer[r * vb->vb_scr_size.tp_col];
 }
 
-void
-vtbuf_init_early(struct vt_buf *vb)
+static void
+vtbuf_do_clearhistory(struct vt_buf *vb)
 {
 	term_rect_t rect;
 	const teken_attr_t *a;
-	term_char_t c;
+	term_char_t ch;
 
+	a = teken_get_curattr(&vb->vb_terminal->tm_emulator);
+	ch = TCOLOR_FG(a->ta_fgcolor) | TCOLOR_BG(a->ta_bgcolor);
+
+	rect.tr_begin.tp_row = rect.tr_begin.tp_col = 0;
+	rect.tr_end.tp_col = vb->vb_scr_size.tp_col;
+	rect.tr_end.tp_row = vb->vb_history_size;
+
+	vtbuf_do_fill(vb, &rect, VTBUF_SPACE_CHAR(ch));
+}
+
+void
+vtbuf_init_early(struct vt_buf *vb)
+{
 	vb->vb_flags |= VBF_CURSOR;
 	vb->vb_roffset = 0;
 	vb->vb_curroffset = 0;
@@ -432,14 +445,7 @@
 	vb->vb_mark_end.tp_col = 0;
 
 	vtbuf_init_rows(vb);
-	rect.tr_begin.tp_row = rect.tr_begin.tp_col = 0;
-	rect.tr_end.tp_col = vb->vb_scr_size.tp_col;
-	rect.tr_end.tp_row = vb->vb_history_size;
-
-	a = teken_get_curattr(&vb->vb_terminal->tm_emulator);
-	c = TCOLOR_FG((term_char_t)a->ta_fgcolor) | 
-	    TCOLOR_BG((term_char_t)a->ta_bgcolor);
-	vtbuf_do_fill(vb, &rect, VTBUF_SPACE_CHAR(c));
+	vtbuf_do_clearhistory(vb);
 	vtbuf_make_undirty(vb);
 	if ((vb->vb_flags & VBF_MTX_INIT) == 0) {
 		mtx_init(&vb->vb_lock, "vtbuf", NULL, MTX_SPIN);
@@ -464,6 +470,14 @@
 	}
 
 	vtbuf_init_early(vb);
+}
+
+void
+vtbuf_clearhistory(struct vt_buf *vb)
+{
+	VTBUF_LOCK(vb);
+	vtbuf_do_clearhistory(vb);
+	VTBUF_UNLOCK(vb);
 }
 
 void
Index: head/sys/dev/vt/vt_core.c
===================================================================
--- head/sys/dev/vt/vt_core.c
+++ head/sys/dev/vt/vt_core.c
@@ -2329,7 +2329,10 @@
 		if (*(int *)data != vd->vd_curwindow->vw_buf.vb_history_size)
 			vtbuf_sethistory_size(&vd->vd_curwindow->vw_buf,
 			    *(int *)data);
-		return 0;
+		return (0);
+	case CONS_CLRHIST:
+		vtbuf_clearhistory(&vd->vd_curwindow->vw_buf);
+		return (0);
 	case CONS_GET:
 		/* XXX */
 		*(int *)data = M_CG640x480;