diff --git a/config.h b/config.h
index 047d735..7ee25e0 100644
--- a/config.h
+++ b/config.h
@@ -7,6 +7,7 @@
  */
 static char font[] = "xos4 Terminus:pixelsize=13:antialias=true:autohint=true";
 static int borderpx = 2;
+#define histsize 2000
 
 /*
  * What program is execed by st depends of these precedence rules:
@@ -161,17 +162,18 @@ static Axiskey ashortcuts[] = {
 #define MODKEY MOD_MASK_ALT
 
 static Shortcut shortcuts[] = {
-	/* modifier                     key                     function        argument */
-	{ MOD_MASK_ANY,                 XKB_KEY_Break,          sendbreak,      {.i =  0} },
-	{ MOD_MASK_CTRL,                XKB_KEY_Print,          toggleprinter,  {.i =  0} },
-	{ MOD_MASK_SHIFT,               XKB_KEY_Print,          printscreen,    {.i =  0} },
-	{ MOD_MASK_ANY,                 XKB_KEY_Print,          printsel,       {.i =  0} },
-	{ MODKEY|MOD_MASK_SHIFT,        XKB_KEY_Prior,          wlzoom,         {.f = +1} },
-	{ MODKEY|MOD_MASK_SHIFT,        XKB_KEY_Next,           wlzoom,         {.f = -1} },
-	{ MODKEY|MOD_MASK_SHIFT,        XKB_KEY_Home,           wlzoomreset,    {.f =  0} },
-	{ MOD_MASK_SHIFT,               XKB_KEY_Insert,         selpaste,       {.i =  0} },
-	{ MODKEY,                       XKB_KEY_Num_Lock,       numlock,        {.i =  0} },
-	{ MODKEY,                       XKB_KEY_Control_L,      iso14755,       {.i =  0} },
+	/* modifier                     key                      function        argument */
+	{ MOD_MASK_ANY,                 XKB_KEY_Break,           sendbreak,      {.i =  0} },
+	{ MOD_MASK_CTRL,                XKB_KEY_Print,           toggleprinter,  {.i =  0} },
+	{ MOD_MASK_SHIFT,               XKB_KEY_Print,           printscreen,    {.i =  0} },
+	{ MOD_MASK_ANY,                 XKB_KEY_Print,           printsel,       {.i =  0} },
+	{ MODKEY|MOD_MASK_SHIFT,        XKB_KEY_Prior,           wlzoom,         {.f = +1} },
+	{ MODKEY|MOD_MASK_SHIFT,        XKB_KEY_Next,            wlzoom,         {.f = -1} },
+	{ MODKEY|MOD_MASK_SHIFT,        XKB_KEY_Home,            wlzoomreset,    {.f =  0} },
+	{ MOD_MASK_SHIFT,               XKB_KEY_Insert,          selpaste,       {.i =  0} },
+	{ MODKEY,                       XKB_KEY_Num_Lock,        numlock,        {.i =  0} },
+	{ MOD_MASK_SHIFT,               XKB_KEY_Page_Up,         kscrollup,      {.i = -1} },
+	{ MOD_MASK_SHIFT,               XKB_KEY_Page_Down,       kscrolldown,    {.i = -1} },
 };
 
 /*
diff --git a/st.c b/st.c
index d905620..12cd91c 100644
--- a/st.c
+++ b/st.c
@@ -93,6 +93,9 @@ char *argv0;
 #define TRUEGREEN(x)		(((x) & 0xff00))
 #define TRUEBLUE(x)		(((x) & 0xff) << 8)
 
+#define TLINE(y)   ((y) < term.scr ? term.hist[((y) + term.histi - term.scr \
+       + histsize + 1) % histsize] : term.line[(y) - term.scr])
+
 /* constants */
 #define ISO14755CMD		"dmenu -p codepoint: </dev/null"
 
@@ -237,25 +240,6 @@ typedef struct {
 	int narg;              /* nb of args */
 } STREscape;
 
-/* Internal representation of the screen */
-typedef struct {
-	int row;      /* nb row */
-	int col;      /* nb col */
-	Line *line;   /* screen */
-	Line *alt;    /* alternate screen */
-	int *dirty;  /* dirtyness of lines */
-	TCursor c;    /* cursor */
-	int top;      /* top    scroll limit */
-	int bot;      /* bottom scroll limit */
-	int mode;     /* terminal mode flags */
-	int esc;      /* escape state flags */
-	char trantbl[4]; /* charset table translation */
-	int charset;  /* current charset */
-	int icharset; /* selected charset for sequence */
-	int numlock; /* lock numbers in keyboard */
-	int *tabs;
-} Term;
-
 typedef struct {
 	struct xkb_context *ctx;
 	struct xkb_keymap *keymap;
@@ -382,10 +366,36 @@ static void printscreen(const Arg *) ;
 static void iso14755(const Arg *);
 static void toggleprinter(const Arg *);
 static void sendbreak(const Arg *);
+static void kscrollup(const Arg *);
+static void kscrolldown(const Arg *);
 
 /* Config.h for applying patches and the configuration. */
 #include "config.h"
 
+/* Internal representation of the screen */
+typedef struct {
+ int row;      /* nb row */
+ int col;      /* nb col */
+ Line *line;   /* screen */
+ Line *alt;    /* alternate screen */
+ Line hist[histsize]; /* history buffer */
+ int histi;    /* history index */
+ int scr;      /* scroll back */
+ int *dirty;  /* dirtyness of lines */
+/* XftGlyphFontSpec *specbuf; /* font spec buffer used for rendering */
+ TCursor c;    /* cursor */
+ int top;      /* top    scroll limit */
+ int bot;      /* bottom scroll limit */
+ int mode;     /* terminal mode flags */
+ int esc;      /* escape state flags */
+ char trantbl[4]; /* charset table translation */
+ int charset;  /* current charset */
+ int icharset; /* selected charset for sequence */
+ int numlock; /* lock numbers in keyboard */
+ int *tabs;
+} Term;
+
+
 /* Font structure */
 typedef struct {
 	int height;
@@ -447,8 +457,8 @@ static void tputtab(int);
 static void tputc(Rune);
 static void treset(void);
 static void tresize(int, int);
-static void tscrollup(int, int);
-static void tscrolldown(int, int);
+static void tscrollup(int, int, int);
+static void tscrolldown(int, int, int);
 static void tsetattr(int *, int);
 static void tsetchar(Rune, Glyph *, int, int);
 static void tsetscroll(int, int);
@@ -800,10 +810,10 @@ tlinelen(int y)
 {
 	int i = term.col;
 
-	if (term.line[y][i - 1].mode & ATTR_WRAP)
+  if (TLINE(y)[i - 1].mode & ATTR_WRAP)
 		return i;
 
-	while (i > 0 && term.line[y][i - 1].u == ' ')
+  while (i > 0 && TLINE(y)[i - 1].u == ' ')
 		--i;
 
 	return i;
@@ -865,7 +875,7 @@ selsnap(int *x, int *y, int direction)
 		 * Snap around if the word wraps around at the end or
 		 * beginning of a line.
 		 */
-		prevgp = &term.line[*y][*x];
+    prevgp = &TLINE(*y)[*x];
 		prevdelim = ISDELIM(prevgp->u);
 		for (;;) {
 			newx = *x + direction;
@@ -880,14 +890,14 @@ selsnap(int *x, int *y, int direction)
 					yt = *y, xt = *x;
 				else
 					yt = newy, xt = newx;
-				if (!(term.line[yt][xt].mode & ATTR_WRAP))
+				if (!(TLINE(yt)[xt].mode & ATTR_WRAP))
 					break;
 			}
 
 			if (newx >= tlinelen(newy))
 				break;
 
-			gp = &term.line[newy][newx];
+			gp = &TLINE(newy)[newx];
 			delim = ISDELIM(gp->u);
 			if (!(gp->mode & ATTR_WDUMMY) && (delim != prevdelim
 					|| (delim && gp->u != prevgp->u)))
@@ -908,14 +918,14 @@ selsnap(int *x, int *y, int direction)
 		*x = (direction < 0) ? 0 : term.col - 1;
 		if (direction < 0) {
 			for (; *y > 0; *y += direction) {
-				if (!(term.line[*y-1][term.col-1].mode
+				if (!(TLINE(*y-1)[term.col-1].mode
 						& ATTR_WRAP)) {
 					break;
 				}
 			}
 		} else if (direction > 0) {
 			for (; *y < term.row-1; *y += direction) {
-				if (!(term.line[*y][term.col-1].mode
+				if (!(TLINE(*y)[term.col-1].mode
 						& ATTR_WRAP)) {
 					break;
 				}
@@ -1048,13 +1058,13 @@ getsel(void)
 		}
 
 		if (sel.type == SEL_RECTANGULAR) {
-			gp = &term.line[y][sel.nb.x];
+			gp = &TLINE(y)[sel.nb.x];
 			lastx = sel.ne.x;
 		} else {
-			gp = &term.line[y][sel.nb.y == y ? sel.nb.x : 0];
+			gp = &TLINE(y)[sel.nb.y == y ? sel.nb.x : 0];
 			lastx = (sel.ne.y == y) ? sel.ne.x : term.col-1;
 		}
-		last = &term.line[y][MIN(lastx, linelen-1)];
+		last = &TLINE(y)[MIN(lastx, linelen-1)];
 		while (last >= gp && last->u == ' ')
 			--last;
 
@@ -1355,6 +1365,10 @@ ttyread(void)
 	if (buflen > 0)
 		memmove(buf, ptr, buflen);
 
+	if (term.scr > 0 && term.scr < histsize-1)
+		term.scr++;
+
+
 	needdraw = true;
 	return ret;
 }
@@ -1365,6 +1379,9 @@ ttywrite(const char *s, size_t n)
 	fd_set wfd, rfd;
 	ssize_t r;
 	size_t lim = 256;
+  Arg arg = (Arg){ .i = term.scr };
+
+	kscrolldown(&arg);
 
 	/*
 	 * Remember that we are using a pty, which might be a modem line.
@@ -1569,13 +1586,53 @@ tswapscreen(void)
 }
 
 void
-tscrolldown(int orig, int n)
+kscrolldown(const Arg* a)
+{
+ int n = a->i;
+
+ if (n < 0)
+   n = term.row + n;
+
+ if (n > term.scr)
+   n = term.scr;
+
+ if (term.scr > 0) {
+   term.scr -= n;
+   selscroll(0, -n);
+   tfulldirt();
+ }
+}
+
+void
+kscrollup(const Arg* a)
+{
+ int n = a->i;
+
+ if (n < 0)
+   n = term.row + n;
+
+ if (term.scr <= histsize - n) {
+   term.scr += n;
+   selscroll(0, n);
+   tfulldirt();
+ }
+}
+
+void
+tscrolldown(int orig, int n, int copyhist)
 {
 	int i;
 	Line temp;
 
 	LIMIT(n, 0, term.bot-orig+1);
 
+	if (copyhist) {
+		term.histi = (term.histi - 1 + histsize) % histsize;
+		temp = term.hist[term.histi];
+		term.hist[term.histi] = term.line[term.bot];
+		term.line[term.bot] = temp;
+	}
+
 	tsetdirt(orig, term.bot-n);
 	tclearregion(0, term.bot-n+1, term.col-1, term.bot);
 
@@ -1589,13 +1646,20 @@ tscrolldown(int orig, int n)
 }
 
 void
-tscrollup(int orig, int n)
+tscrollup(int orig, int n, int copyhist)
 {
 	int i;
 	Line temp;
 
 	LIMIT(n, 0, term.bot-orig+1);
 
+	if (copyhist) {
+		term.histi = (term.histi + 1) % histsize;
+		temp = term.hist[term.histi];
+		term.hist[term.histi] = term.line[orig];
+		term.line[orig] = temp;
+	}
+
 	tclearregion(0, orig, term.col-1, orig+n-1);
 	tsetdirt(orig+n, term.bot);
 
@@ -1644,7 +1708,7 @@ tnewline(int first_col)
 	int y = term.c.y;
 
 	if (y == term.bot) {
-		tscrollup(term.top, 1);
+		tscrollup(term.top, 1, 1);
 	} else {
 		y++;
 	}
@@ -1809,14 +1873,14 @@ void
 tinsertblankline(int n)
 {
 	if (BETWEEN(term.c.y, term.top, term.bot))
-		tscrolldown(term.c.y, n);
+		tscrolldown(term.c.y, n, 0);
 }
 
 void
 tdeleteline(int n)
 {
 	if (BETWEEN(term.c.y, term.top, term.bot))
-		tscrollup(term.c.y, n);
+		tscrollup(term.c.y, n, 0);
 }
 
 int32_t
@@ -2246,11 +2310,11 @@ csihandle(void)
 		break;
 	case 'S': /* SU -- Scroll <n> line up */
 		DEFAULT(csiescseq.arg[0], 1);
-		tscrollup(term.top, csiescseq.arg[0]);
+		tscrollup(term.top, csiescseq.arg[0], 0);
 		break;
 	case 'T': /* SD -- Scroll <n> line down */
 		DEFAULT(csiescseq.arg[0], 1);
-		tscrolldown(term.top, csiescseq.arg[0]);
+		tscrolldown(term.top, csiescseq.arg[0], 0);
 		break;
 	case 'L': /* IL -- Insert <n> blank lines */
 		DEFAULT(csiescseq.arg[0], 1);
@@ -2787,7 +2851,7 @@ eschandle(uchar ascii)
 		return 0;
 	case 'D': /* IND -- Linefeed */
 		if (term.c.y == term.bot) {
-			tscrollup(term.top, 1);
+			tscrollup(term.top, 1, 1);
 		} else {
 			tmoveto(term.c.x, term.c.y+1);
 		}
@@ -2800,7 +2864,7 @@ eschandle(uchar ascii)
 		break;
 	case 'M': /* RI -- Reverse index */
 		if (term.c.y == term.top) {
-			tscrolldown(term.top, 1);
+			tscrolldown(term.top, 1, 1);
 		} else {
 			tmoveto(term.c.x, term.c.y-1);
 		}
@@ -2987,7 +3051,7 @@ check_control_code:
 void
 tresize(int col, int row)
 {
-	int i;
+	int i, j;
 	int minrow = MIN(row, term.row);
 	int mincol = MIN(col, term.col);
 	int *bp;
@@ -3024,6 +3088,14 @@ tresize(int col, int row)
 	term.dirty = xrealloc(term.dirty, row * sizeof(*term.dirty));
 	term.tabs = xrealloc(term.tabs, col * sizeof(*term.tabs));
 
+  for (i = 0; i < histsize; i++) {
+    term.hist[i] = xrealloc(term.hist[i], col * sizeof(Glyph));
+    for (j = mincol; j < col; j++) {
+      term.hist[i][j] = term.c.attr;
+      term.hist[i][j].u = ' ';
+    }
+  }
+
 	/* resize each row to new width, zero-pad if needed */
 	for (i = 0; i < minrow; i++) {
 		term.line[i] = xrealloc(term.line[i], col * sizeof(Glyph));
@@ -3413,11 +3485,22 @@ wlinit(void)
 	wl.surface = wl_compositor_create_surface(wl.cmp);
 	wl_surface_add_listener(wl.surface, &surflistener, NULL);
 
+	if (wl.shell == NULL)
+		die("wl.shell is not initialized.\n");
+
 	wl.xdgsurface = zxdg_shell_v6_get_xdg_surface(wl.shell, wl.surface);
+	if (wl.xdgsurface == NULL)
+		die("wl.xdgsurface is not initialized.\n");
+
 	zxdg_surface_v6_add_listener(wl.xdgsurface, &xdgsurflistener, NULL);
+
 	wl.xdgtoplevel = zxdg_surface_v6_get_toplevel(wl.xdgsurface);
+	if (wl.xdgtoplevel == NULL)
+		die("wl.xdgtoplevel is not initialized.\n");
+
 	zxdg_toplevel_v6_set_app_id(wl.xdgtoplevel,
 		opt_class ? opt_class : termname);
+
 	zxdg_toplevel_v6_add_listener(wl.xdgtoplevel, &xdgtoplevellistener,
 		NULL);
 
@@ -3845,10 +3928,10 @@ drawregion(int x1, int y1, int x2, int y2)
 			continue;
 
 		term.dirty[y] = 0;
-		base = term.line[y][0];
+		base = TLINE(y)[0];
 		ic = ib = ox = 0;
 		for (x = x1; x < x2; x++) {
-			new = term.line[y][x];
+			new = TLINE(y)[x];
 			if (new.mode == ATTR_WDUMMY)
 				continue;
 			if (ena_sel && selected(x, y))
@@ -3869,7 +3952,8 @@ drawregion(int x1, int y1, int x2, int y2)
 		if (ib > 0)
 			wldraws(buf, base, ox, y, ic, ib);
 	}
-	wldrawcursor();
+	if(term.scr == 0)
+		wldrawcursor();
 }
 
 void
@@ -3957,6 +4041,8 @@ regglobal(void *data, struct wl_registry *registry, uint32_t name,
 	} else if (strcmp(interface, "zxdg_shell_v6") == 0) {
 		wl.shell = wl_registry_bind(registry, name,
 				&zxdg_shell_v6_interface, 1);
+		if(wl.shell == NULL)
+			die("wl.shell is null.\n");
 		zxdg_shell_v6_add_listener(wl.shell, &xdgshelllistener, NULL);
 	} else if (strcmp(interface, "wl_shm") == 0) {
 		wl.shm = wl_registry_bind(registry, name, &wl_shm_interface, 1);