diff --git a/cmd-attach-session.c b/cmd-attach-session.c
index e9c23df3..079b22f3 100644
--- a/cmd-attach-session.c
+++ b/cmd-attach-session.c
@@ -54,8 +54,7 @@ cmd_attach_session(struct cmdq_item *item, int dflag, int rflag,
 	struct client		*c = item->client, *c_loop;
 	struct winlink		*wl = item->state.tflag.wl;
 	struct window_pane	*wp = item->state.tflag.wp;
-	char			*cause, *cwd;
-	struct format_tree	*ft;
+	char			*cause;
 
 	if (RB_EMPTY(&sessions)) {
 		cmdq_error(item, "no sessions");
@@ -77,13 +76,8 @@ cmd_attach_session(struct cmdq_item *item, int dflag, int rflag,
 	}
 
 	if (cflag != NULL) {
-		ft = format_create(item, FORMAT_NONE, 0);
-		format_defaults(ft, c, s, wl, wp);
-		cwd = format_expand(ft, cflag);
-		format_free(ft);
-
 		free((void *)s->cwd);
-		s->cwd = cwd;
+		s->cwd = format_single(item, cflag, c, s, wl, wp);
 	}
 
 	if (c->session != NULL) {
diff --git a/cmd-break-pane.c b/cmd-break-pane.c
index fdefeb17..3c564a0c 100644
--- a/cmd-break-pane.c
+++ b/cmd-break-pane.c
@@ -48,6 +48,7 @@ static enum cmd_retval
 cmd_break_pane_exec(struct cmd *self, struct cmdq_item *item)
 {
 	struct args		*args = self->args;
+	struct client		*c = item->state.c;
 	struct winlink		*wl = item->state.sflag.wl;
 	struct session		*src_s = item->state.sflag.s;
 	struct session		*dst_s = item->state.tflag.s;
@@ -55,7 +56,6 @@ cmd_break_pane_exec(struct cmd *self, struct cmdq_item *item)
 	struct window		*w = wl->window;
 	char			*name, *cause;
 	int			 idx = item->state.tflag.idx;
-	struct format_tree	*ft;
 	const char		*template;
 	char			*cp;
 
@@ -106,15 +106,9 @@ cmd_break_pane_exec(struct cmd *self, struct cmdq_item *item)
 	if (args_has(args, 'P')) {
 		if ((template = args_get(args, 'F')) == NULL)
 			template = BREAK_PANE_TEMPLATE;
-
-		ft = format_create(item, FORMAT_NONE, 0);
-		format_defaults(ft, item->state.c, dst_s, wl, wp);
-
-		cp = format_expand(ft, template);
+		cp = format_single(item, template, c, dst_s, wl, wp);
 		cmdq_print(item, "%s", cp);
 		free(cp);
-
-		format_free(ft);
 	}
 	return (CMD_RETURN_NORMAL);
 }
diff --git a/cmd-if-shell.c b/cmd-if-shell.c
index ec4bf68e..f7d95d53 100644
--- a/cmd-if-shell.c
+++ b/cmd-if-shell.c
@@ -69,10 +69,10 @@ cmd_if_shell_exec(struct cmd *self, struct cmdq_item *item)
 	char				*shellcmd, *cmd, *cause;
 	struct cmd_list			*cmdlist;
 	struct cmdq_item		*new_item;
+	struct client			*c = item->state.c;
 	struct session			*s = item->state.tflag.s;
 	struct winlink			*wl = item->state.tflag.wl;
 	struct window_pane		*wp = item->state.tflag.wp;
-	struct format_tree		*ft;
 	const char			*cwd;
 
 	if (item->client != NULL && item->client->session == NULL)
@@ -82,11 +82,7 @@ cmd_if_shell_exec(struct cmd *self, struct cmdq_item *item)
 	else
 		cwd = NULL;
 
-	ft = format_create(item, FORMAT_NONE, 0);
-	format_defaults(ft, item->state.c, s, wl, wp);
-	shellcmd = format_expand(ft, args->argv[0]);
-	format_free(ft);
-
+	shellcmd = format_single(item, args->argv[0], c, s, wl, wp);
 	if (args_has(args, 'F')) {
 		cmd = NULL;
 		if (*shellcmd != '0' && *shellcmd != '\0')
diff --git a/cmd-new-session.c b/cmd-new-session.c
index 08fc6065..a5b197b0 100644
--- a/cmd-new-session.c
+++ b/cmd-new-session.c
@@ -78,7 +78,6 @@ cmd_new_session_exec(struct cmd *self, struct cmdq_item *item)
 	char		       **argv, *cause, *cp;
 	int			 detached, already_attached, idx, argc;
 	u_int			 sx, sy;
-	struct format_tree	*ft;
 	struct environ_entry	*envent;
 	struct cmd_find_state	 fs;
 
@@ -155,10 +154,8 @@ cmd_new_session_exec(struct cmd *self, struct cmdq_item *item)
 
 	/* Get the new session working directory. */
 	if (args_has(args, 'c')) {
-		ft = format_create(item, FORMAT_NONE, 0);
-		format_defaults(ft, c, NULL, NULL, NULL);
-		to_free = cwd = format_expand(ft, args_get(args, 'c'));
-		format_free(ft);
+		cwd = args_get(args, 'c');
+		to_free = cwd = format_single(item, cwd, c, NULL, NULL, NULL);
 	} else if (c != NULL && c->session == NULL && c->cwd != NULL)
 		cwd = c->cwd;
 	else
@@ -322,15 +319,9 @@ cmd_new_session_exec(struct cmd *self, struct cmdq_item *item)
 	if (args_has(args, 'P')) {
 		if ((template = args_get(args, 'F')) == NULL)
 			template = NEW_SESSION_TEMPLATE;
-
-		ft = format_create(item, FORMAT_NONE, 0);
-		format_defaults(ft, c, s, NULL, NULL);
-
-		cp = format_expand(ft, template);
+		cp = format_single(item, template, c, s, NULL, NULL);
 		cmdq_print(item, "%s", cp);
 		free(cp);
-
-		format_free(ft);
 	}
 
 	if (!detached)
diff --git a/cmd-new-window.c b/cmd-new-window.c
index 082b7443..c10a4aaf 100644
--- a/cmd-new-window.c
+++ b/cmd-new-window.c
@@ -59,7 +59,6 @@ cmd_new_window_exec(struct cmd *self, struct cmdq_item *item)
 	const char		*cmd, *path, *template, *cwd, *to_free;
 	char		       **argv, *cause, *cp;
 	int			 argc, detached;
-	struct format_tree	*ft;
 	struct environ_entry	*envent;
 	struct cmd_find_state	 fs;
 
@@ -95,10 +94,8 @@ cmd_new_window_exec(struct cmd *self, struct cmdq_item *item)
 
 	to_free = NULL;
 	if (args_has(args, 'c')) {
-		ft = format_create(item, FORMAT_NONE, 0);
-		format_defaults(ft, c, s, NULL, NULL);
-		cwd = to_free = format_expand(ft, args_get(args, 'c'));
-		format_free(ft);
+		cwd = args_get(args, 'c');
+		to_free = cwd = format_single(item, cwd, c, s, NULL, NULL);
 	} else if (item->client != NULL && item->client->session == NULL)
 		cwd = item->client->cwd;
 	else
@@ -142,15 +139,9 @@ cmd_new_window_exec(struct cmd *self, struct cmdq_item *item)
 	if (args_has(args, 'P')) {
 		if ((template = args_get(args, 'F')) == NULL)
 			template = NEW_WINDOW_TEMPLATE;
-
-		ft = format_create(item, FORMAT_NONE, 0);
-		format_defaults(ft, c, s, wl, NULL);
-
-		cp = format_expand(ft, template);
+		cp = format_single(item, template, c, s, wl, NULL);
 		cmdq_print(item, "%s", cp);
 		free(cp);
-
-		format_free(ft);
 	}
 
 	if (to_free != NULL)
diff --git a/cmd-run-shell.c b/cmd-run-shell.c
index e6cd7936..d06d7f99 100644
--- a/cmd-run-shell.c
+++ b/cmd-run-shell.c
@@ -86,11 +86,10 @@ cmd_run_shell_exec(struct cmd *self, struct cmdq_item *item)
 {
 	struct args			*args = self->args;
 	struct cmd_run_shell_data	*cdata;
-	char				*shellcmd;
+	struct client			*c = item->state.c;
 	struct session			*s = item->state.tflag.s;
 	struct winlink			*wl = item->state.tflag.wl;
 	struct window_pane		*wp = item->state.tflag.wp;
-	struct format_tree		*ft;
 	const char			*cwd;
 
 	if (item->client != NULL && item->client->session == NULL)
@@ -100,13 +99,8 @@ cmd_run_shell_exec(struct cmd *self, struct cmdq_item *item)
 	else
 		cwd = NULL;
 
-	ft = format_create(item, FORMAT_NONE, 0);
-	format_defaults(ft, item->state.c, s, wl, wp);
-	shellcmd = format_expand(ft, args->argv[0]);
-	format_free(ft);
-
 	cdata = xcalloc(1, sizeof *cdata);
-	cdata->cmd = shellcmd;
+	cdata->cmd = format_single(item, args->argv[0], c, s, wl, wp);
 
 	if (args_has(args, 't') && wp != NULL)
 		cdata->wp_id = wp->id;
@@ -116,7 +110,7 @@ cmd_run_shell_exec(struct cmd *self, struct cmdq_item *item)
 	if (!args_has(args, 'b'))
 		cdata->item = item;
 
-	job_run(shellcmd, s, cwd, cmd_run_shell_callback, cmd_run_shell_free,
+	job_run(cdata->cmd, s, cwd, cmd_run_shell_callback, cmd_run_shell_free,
 	    cdata);
 
 	if (args_has(args, 'b'))
diff --git a/cmd-split-window.c b/cmd-split-window.c
index f05dc249..064d1f5f 100644
--- a/cmd-split-window.c
+++ b/cmd-split-window.c
@@ -54,6 +54,7 @@ static enum cmd_retval
 cmd_split_window_exec(struct cmd *self, struct cmdq_item *item)
 {
 	struct args		*args = self->args;
+	struct client		*c = item->state.c;
 	struct session		*s = item->state.tflag.s;
 	struct winlink		*wl = item->state.tflag.wl;
 	struct window		*w = wl->window;
@@ -65,7 +66,6 @@ cmd_split_window_exec(struct cmd *self, struct cmdq_item *item)
 	int			 argc, size, percentage;
 	enum layout_type	 type;
 	struct layout_cell	*lc;
-	struct format_tree	*ft;
 	struct environ_entry	*envent;
 	struct cmd_find_state    fs;
 
@@ -92,10 +92,8 @@ cmd_split_window_exec(struct cmd *self, struct cmdq_item *item)
 
 	to_free = NULL;
 	if (args_has(args, 'c')) {
-		ft = format_create(item, FORMAT_NONE, 0);
-		format_defaults(ft, item->state.c, s, NULL, NULL);
-		to_free = cwd = format_expand(ft, args_get(args, 'c'));
-		format_free(ft);
+		cwd = args_get(args, 'c');
+		to_free = cwd = format_single(item, cwd, c, s, NULL, NULL);
 	} else if (item->client != NULL && item->client->session == NULL)
 		cwd = item->client->cwd;
 	else
@@ -168,15 +166,9 @@ cmd_split_window_exec(struct cmd *self, struct cmdq_item *item)
 	if (args_has(args, 'P')) {
 		if ((template = args_get(args, 'F')) == NULL)
 			template = SPLIT_WINDOW_TEMPLATE;
-
-		ft = format_create(item, FORMAT_NONE, 0);
-		format_defaults(ft, item->state.c, s, wl, new_wp);
-
-		cp = format_expand(ft, template);
+		cp = format_single(item, template, c, s, wl, new_wp);
 		cmdq_print(item, "%s", cp);
 		free(cp);
-
-		format_free(ft);
 	}
 	notify_window("window-layout-changed", w);
 
diff --git a/control-notify.c b/control-notify.c
index 3b2d32eb..230bce61 100644
--- a/control-notify.c
+++ b/control-notify.c
@@ -64,10 +64,9 @@ control_notify_window_layout_changed(struct window *w)
 {
 	struct client		*c;
 	struct session		*s;
-	struct format_tree	*ft;
 	struct winlink		*wl;
 	const char		*template;
-	char			*expanded;
+	char			*cp;
 
 	template = "%layout-change #{window_id} #{window_layout} "
 	    "#{window_visible_layout} #{window_flags}";
@@ -88,15 +87,12 @@ control_notify_window_layout_changed(struct window *w)
 		if (w->layout_root == NULL)
 			continue;
 
-		ft = format_create(NULL, FORMAT_NONE, 0);
 		wl = winlink_find_by_window(&s->windows, w);
 		if (wl != NULL) {
-			format_defaults(ft, c, NULL, wl, NULL);
-			expanded = format_expand(ft, template);
-			control_write(c, "%s", expanded);
-			free(expanded);
+			cp = format_single(NULL, template, c, NULL, wl, NULL);
+			control_write(c, "%s", cp);
+			free(cp);
 		}
-		format_free(ft);
 	}
 }
 
diff --git a/format.c b/format.c
index 4df17025..7e78897f 100644
--- a/format.c
+++ b/format.c
@@ -500,7 +500,6 @@ format_merge(struct format_tree *ft, struct format_tree *from)
 		if (fe->value != NULL)
 			format_add(ft, fe->key, "%s", fe->value);
 	}
-
 }
 
 /* Create a new tree. */
@@ -1061,6 +1060,22 @@ format_expand(struct format_tree *ft, const char *fmt)
 	return (buf);
 }
 
+/* Expand a single string. */
+char *
+format_single(struct cmdq_item *item, const char *fmt, struct client *c,
+    struct session *s, struct winlink *wl, struct window_pane *wp)
+{
+	struct format_tree	*ft;
+	char			*expanded;
+
+	ft = format_create(item, FORMAT_NONE, 0);
+	format_defaults(ft, c, s, wl, wp);
+
+	expanded = format_expand(ft, fmt);
+	format_free(ft);
+	return (expanded);
+}
+
 /* Set defaults for any of arguments that are not NULL. */
 void
 format_defaults(struct format_tree *ft, struct client *c, struct session *s,
diff --git a/tmux.h b/tmux.h
index 40b62e0c..61ce665b 100644
--- a/tmux.h
+++ b/tmux.h
@@ -1508,6 +1508,9 @@ void printflike(3, 4) format_add(struct format_tree *, const char *,
 		     const char *, ...);
 char		*format_expand_time(struct format_tree *, const char *, time_t);
 char		*format_expand(struct format_tree *, const char *);
+char		*format_single(struct cmdq_item *, const char *,
+		     struct client *, struct session *, struct winlink *,
+		     struct window_pane *);
 void		 format_defaults(struct format_tree *, struct client *,
 		     struct session *, struct winlink *, struct window_pane *);
 void		 format_defaults_window(struct format_tree *, struct window *);
diff --git a/window-copy.c b/window-copy.c
index cb6243db..bf7dae56 100644
--- a/window-copy.c
+++ b/window-copy.c
@@ -1604,29 +1604,23 @@ window_copy_copy_buffer(struct window_pane *wp, const char *bufname, void *buf,
 }
 
 static void
-window_copy_copy_pipe(struct window_pane *wp, struct session *sess,
+window_copy_copy_pipe(struct window_pane *wp, struct session *s,
     const char *bufname, const char *arg)
 {
-	void			*buf;
-	size_t			 len;
-	struct job		*job;
-	struct format_tree	*ft;
-	char			*expanded;
+	void		*buf;
+	size_t		 len;
+	struct job	*job;
+	char		*expanded;
 
 	buf = window_copy_get_selection(wp, &len);
 	if (buf == NULL)
 		return;
+	expanded = format_single(NULL, arg, NULL, s, NULL, wp);
 
-	ft = format_create(NULL, FORMAT_NONE, 0);
-	format_defaults(ft, NULL, sess, NULL, wp);
-	expanded = format_expand(ft, arg);
-
-	job = job_run(expanded, sess, NULL, NULL, NULL, NULL);
+	job = job_run(expanded, s, NULL, NULL, NULL, NULL);
 	bufferevent_write(job->event, buf, len);
 
 	free(expanded);
-	format_free(ft);
-
 	window_copy_copy_buffer(wp, bufname, buf, len);
 }