diff --git a/client.c b/client.c
index 9c493dfa..9a5ae455 100644
--- a/client.c
+++ b/client.c
@@ -354,6 +354,7 @@ client_send_identify(int flags)
 {
 	const char	 *s;
 	char		**ss;
+	size_t		  sslen;
 	int		  fd;
 	pid_t		  pid;
 
@@ -378,8 +379,11 @@ client_send_identify(int flags)
 	pid = getpid();
 	client_write_one(MSG_IDENTIFY_CLIENTPID, -1, &pid, sizeof pid);
 
-	for (ss = environ; *ss != NULL; ss++)
-		client_write_one(MSG_IDENTIFY_ENVIRON, -1, *ss, strlen(*ss) + 1);
+	for (ss = environ; *ss != NULL; ss++) {
+		sslen = strlen(*ss) + 1;
+		if (sslen <= MAX_IMSGSIZE - IMSG_HEADER_SIZE)
+			client_write_one(MSG_IDENTIFY_ENVIRON, -1, *ss, sslen);
+	}
 
 	client_write_one(MSG_IDENTIFY_DONE, -1, NULL, 0);
 
diff --git a/cmd-show-environment.c b/cmd-show-environment.c
index 7737752f..a61cf3f4 100644
--- a/cmd-show-environment.c
+++ b/cmd-show-environment.c
@@ -27,16 +27,61 @@
  * Show environment.
  */
 
-enum cmd_retval	 cmd_show_environment_exec(struct cmd *, struct cmd_q *);
+enum cmd_retval	cmd_show_environment_exec(struct cmd *, struct cmd_q *);
+
+char	*cmd_show_environment_escape(struct environ_entry *);
+void	 cmd_show_environment_print(struct cmd *, struct cmd_q *,
+	     struct environ_entry *);
 
 const struct cmd_entry cmd_show_environment_entry = {
 	"show-environment", "showenv",
-	"gt:", 0, 1,
-	"[-g] " CMD_TARGET_SESSION_USAGE " [name]",
+	"gst:", 0, 1,
+	"[-gs] " CMD_TARGET_SESSION_USAGE " [name]",
 	0,
 	cmd_show_environment_exec
 };
 
+char *
+cmd_show_environment_escape(struct environ_entry *envent)
+{
+	const char	*value = envent->value;
+	char		 c, *out, *ret;
+
+	out = ret = xmalloc(strlen(value) * 2 + 1); /* at most twice the size */
+	while ((c = *value++) != '\0') {
+		/* POSIX interprets $ ` " and \ in double quotes. */
+		if (c == '$' || c == '`' || c == '"' || c == '\\')
+			*out++ = '\\';
+		*out++ = c;
+	}
+	*out = '\0';
+
+	return ret;
+}
+
+void
+cmd_show_environment_print(struct cmd *self, struct cmd_q *cmdq,
+    struct environ_entry *envent)
+{
+	char	*escaped;
+
+	if (!args_has(self->args, 's')) {
+		if (envent->value != NULL)
+			cmdq_print(cmdq, "%s=%s", envent->name, envent->value);
+		else
+			cmdq_print(cmdq, "-%s", envent->name);
+		return;
+	}
+
+	if (envent->value != NULL) {
+		escaped = cmd_show_environment_escape(envent);
+		cmdq_print(cmdq, "%s=\"%s\"; export %s;", envent->name, escaped,
+		    envent->name);
+		free(escaped);
+	} else
+		cmdq_print(cmdq, "unset %s;", envent->name);
+}
+
 enum cmd_retval
 cmd_show_environment_exec(struct cmd *self, struct cmd_q *cmdq)
 {
@@ -48,7 +93,8 @@ cmd_show_environment_exec(struct cmd *self, struct cmd_q *cmdq)
 	if (args_has(self->args, 'g'))
 		env = &global_environ;
 	else {
-		if ((s = cmd_find_session(cmdq, args_get(args, 't'), 0)) == NULL)
+		s = cmd_find_session(cmdq, args_get(args, 't'), 0);
+		if (s == NULL)
 			return (CMD_RETURN_ERROR);
 		env = &s->environ;
 	}
@@ -59,19 +105,11 @@ cmd_show_environment_exec(struct cmd *self, struct cmd_q *cmdq)
 			cmdq_error(cmdq, "unknown variable: %s", args->argv[0]);
 			return (CMD_RETURN_ERROR);
 		}
-		if (envent->value != NULL)
-			cmdq_print(cmdq, "%s=%s", envent->name, envent->value);
-		else
-			cmdq_print(cmdq, "-%s", envent->name);
+		cmd_show_environment_print(self, cmdq, envent);
 		return (CMD_RETURN_NORMAL);
 	}
 
-	RB_FOREACH(envent, environ, env) {
-		if (envent->value != NULL)
-			cmdq_print(cmdq, "%s=%s", envent->name, envent->value);
-		else
-			cmdq_print(cmdq, "-%s", envent->name);
-	}
-
+	RB_FOREACH(envent, environ, env)
+		cmd_show_environment_print(self, cmdq, envent);
 	return (CMD_RETURN_NORMAL);
 }
diff --git a/format.c b/format.c
index 59ef598c..8f74c415 100644
--- a/format.c
+++ b/format.c
@@ -712,6 +712,8 @@ format_defaults_client(struct format_tree *ft, struct client *c)
 		format_add(ft, "client_tty", "%s", c->tty.path);
 	if (c->tty.termname != NULL)
 		format_add(ft, "client_termname", "%s", c->tty.termname);
+	format_add(ft, "client_control_mode", "%d",
+		!!(c->flags & CLIENT_CONTROL));
 
 	t = c->creation_time.tv_sec;
 	format_add(ft, "client_created", "%lld", (long long) t);
diff --git a/input.c b/input.c
index d1ff17fe..095816c3 100644
--- a/input.c
+++ b/input.c
@@ -801,10 +801,7 @@ input_reset(struct window_pane *wp)
 {
 	struct input_ctx	*ictx = wp->ictx;
 
-	memcpy(&ictx->cell, &grid_default_cell, sizeof ictx->cell);
-	memcpy(&ictx->old_cell, &ictx->cell, sizeof ictx->old_cell);
-	ictx->old_cx = 0;
-	ictx->old_cy = 0;
+	input_reset_cell(ictx);
 
 	if (wp->mode == NULL)
 		screen_write_start(&ictx->ctx, wp, &wp->base);
diff --git a/screen-write.c b/screen-write.c
index e38c9f53..37e2b548 100644
--- a/screen-write.c
+++ b/screen-write.c
@@ -795,6 +795,8 @@ screen_write_linefeed(struct screen_write_ctx *ctx, int wrapped)
 	gl = &s->grid->linedata[s->grid->hsize + s->cy];
 	if (wrapped)
 		gl->flags |= GRID_LINE_WRAPPED;
+	else
+		gl->flags &= ~GRID_LINE_WRAPPED;
 
 	if (s->cy == s->rlower)
 		grid_view_scroll_region_up(s->grid, s->rupper, s->rlower);
diff --git a/server-client.c b/server-client.c
index c9c0c3ef..59969618 100644
--- a/server-client.c
+++ b/server-client.c
@@ -95,6 +95,8 @@ server_client_create(int fd)
 
 	environ_init(&c->environ);
 
+	c->cwd = -1;
+
 	c->cmdq = cmdq_new(c);
 	c->cmdq->client_exit = 1;
 
@@ -1267,12 +1269,11 @@ server_client_msg_identify(struct client *c, struct imsg *imsg)
 
 	if (c->fd == -1)
 		return;
-	if (!isatty(c->fd)) {
+	if (tty_init(&c->tty, c, c->fd, c->term) != 0) {
 		close(c->fd);
 		c->fd = -1;
 		return;
 	}
-	tty_init(&c->tty, c, c->fd, c->term);
 	if (c->flags & CLIENT_UTF8)
 		c->tty.flags |= TTY_UTF8;
 	if (c->flags & CLIENT_256COLOURS)
diff --git a/tmux.1 b/tmux.1
index 20754551..18626052 100644
--- a/tmux.1
+++ b/tmux.1
@@ -3362,6 +3362,7 @@ The following variables are available, where appropriate:
 .It Li "client_activity_string" Ta "" Ta "String time client last had activity"
 .It Li "client_created" Ta "" Ta "Integer time client created"
 .It Li "client_created_string" Ta "" Ta "String time client created"
+.It Li "client_control_mode" Ta "" Ta "1 if client is in control mode"
 .It Li "client_height" Ta "" Ta "Height of client"
 .It Li "client_last_session" Ta "" Ta "Name of the client's last session"
 .It Li "client_pid" Ta "" Ta "PID of client process"
@@ -3547,7 +3548,7 @@ flag unsets a variable.
 indicates the variable is to be removed from the environment before starting a
 new process.
 .It Xo Ic show-environment
-.Op Fl g
+.Op Fl gs
 .Op Fl t Ar target-session
 .Op Ar variable
 .Xc
@@ -3561,6 +3562,9 @@ If
 is omitted, all variables are shown.
 Variables removed from the environment are prefixed with
 .Ql - .
+If
+.Fl s
+is used, the output is formatted as a set of Bourne shell commands.
 .El
 .Sh STATUS LINE
 .Nm
diff --git a/tmux.h b/tmux.h
index f0fef0d5..f0f0d13c 100644
--- a/tmux.h
+++ b/tmux.h
@@ -1604,7 +1604,7 @@ void	tty_putcode_ptr2(struct tty *, enum tty_code_code, const void *,
 void	tty_puts(struct tty *, const char *);
 void	tty_putc(struct tty *, u_char);
 void	tty_putn(struct tty *, const void *, size_t, u_int);
-void	tty_init(struct tty *, struct client *, int, char *);
+int	tty_init(struct tty *, struct client *, int, char *);
 int	tty_resize(struct tty *);
 int	tty_set_size(struct tty *, u_int, u_int);
 void	tty_set_class(struct tty *, u_int);
diff --git a/tty.c b/tty.c
index 63380c29..374fb8c6 100644
--- a/tty.c
+++ b/tty.c
@@ -59,11 +59,14 @@ void	tty_default_colours(struct grid_cell *, const struct window_pane *);
 #define tty_pane_full_width(tty, ctx) \
 	((ctx)->xoff == 0 && screen_size_x((ctx)->wp->screen) >= (tty)->sx)
 
-void
+int
 tty_init(struct tty *tty, struct client *c, int fd, char *term)
 {
 	char	*path;
 
+	if (!isatty(fd))
+		return (-1);
+
 	memset(tty, 0, sizeof *tty);
 	tty->log_fd = -1;
 
@@ -75,13 +78,15 @@ tty_init(struct tty *tty, struct client *c, int fd, char *term)
 	tty->client = c;
 
 	if ((path = ttyname(fd)) == NULL)
-		fatalx("ttyname failed");
+		return (-1);
 	tty->path = xstrdup(path);
 	tty->cstyle = 0;
 	tty->ccolour = xstrdup("");
 
 	tty->flags = 0;
 	tty->term_flags = 0;
+
+	return (0);
 }
 
 int