If multiple arguments are given to new-session, new-window,

split-window, respawn-window or respawn-pane, pass them directly to
execvp() to help avoid quoting problems. One argument still goes to "sh
-c" like before. Requested by many over the years. Patch from J Raynor.

cmd-new-session.c

@@ -35,10 +35,10 @@ enum cmd_retval	 cmd_new_session_exec(struct cmd *, struct cmd_q *);
 
 const struct cmd_entry cmd_new_session_entry = {
 	"new-session", "new",
-	"Ac:dDF:n:Ps:t:x:y:", 0, 1,
+	"Ac:dDF:n:Ps:t:x:y:", 0, -1,
 	"[-AdDP] [-c start-directory] [-F format] [-n window-name] "
-	"[-s session-name] " CMD_TARGET_SESSION_USAGE " [-x width] [-y height] "
+	"[-s session-name] " CMD_TARGET_SESSION_USAGE " [-x width] "
-	"[command]",
+	"[-y height] [command]",
 	CMD_STARTSERVER|CMD_CANTNEST,
 	NULL,
 	cmd_new_session_exec
@@ -55,8 +55,9 @@ cmd_new_session_exec(struct cmd *self, struct cmd_q *cmdq)
 	struct termios		 tio, *tiop;
 	const char		*newname, *target, *update, *errstr, *template;
 	const char		*path;
-	char			*cmd, *cause, *cp;
+	char		       **argv, *cmd, *cause, *cp;
 	int			 detached, already_attached, idx, cwd, fd = -1;
+	int			 argc;
 	u_int			 sx, sy;
 	struct format_tree	*ft;
 	struct environ_entry	*envent;
@@ -183,12 +184,21 @@ cmd_new_session_exec(struct cmd *self, struct cmd_q *cmdq)
 		sy = 1;
 
 	/* Figure out the command for the new window. */
-	if (target != NULL)
+	argc = -1;
-		cmd = NULL;
+	argv = NULL;
-	else if (args->argc != 0)
+	if (target == NULL && args->argc != 0) {
-		cmd = args->argv[0];
+		argc = args->argc;
-	else
+		argv = args->argv;
+	} else if (target == NULL) {
 		cmd = options_get_string(&global_s_options, "default-command");
+		if (cmd != NULL && *cmd != '\0') {
+			argc = 1;
+			argv = &cmd;
+		} else {
+			argc = 0;
+			argv = NULL;
+		}
+	}
 
 	path = NULL;
 	if (c != NULL && c->session == NULL)
@@ -206,8 +216,8 @@ cmd_new_session_exec(struct cmd *self, struct cmd_q *cmdq)
 
 	/* Create the new session. */
 	idx = -1 - options_get_number(&global_s_options, "base-index");
-	s = session_create(newname, cmd, path, cwd, &env, tiop, idx, sx, sy,
+	s = session_create(newname, argc, argv, path, cwd, &env, tiop, idx, sx,
-	    &cause);
+	    sy, &cause);
 	if (s == NULL) {
 		cmdq_error(cmdq, "create session failed: %s", cause);
 		free(cause);
@@ -216,7 +226,7 @@ cmd_new_session_exec(struct cmd *self, struct cmd_q *cmdq)
 	environ_free(&env);
 
 	/* Set the initial window name if one given. */
-	if (cmd != NULL && args_has(args, 'n')) {
+	if (argc >= 0 && args_has(args, 'n')) {
 		w = s->curw->window;
 		window_set_name(w, args_get(args, 'n'));
 		options_set_number(&w->options, "automatic-rename", 0);

cmd-new-window.c

@@ -34,7 +34,7 @@ enum cmd_retval	cmd_new_window_exec(struct cmd *, struct cmd_q *);
 
 const struct cmd_entry cmd_new_window_entry = {
 	"new-window", "neww",
-	"ac:dF:kn:Pt:", 0, 1,
+	"ac:dF:kn:Pt:", 0, -1,
 	"[-adkP] [-c start-directory] [-F format] [-n window-name] "
 	CMD_TARGET_WINDOW_USAGE " [command]",
 	0,
@@ -50,8 +50,8 @@ cmd_new_window_exec(struct cmd *self, struct cmd_q *cmdq)
 	struct winlink		*wl;
 	struct client		*c;
 	const char		*cmd, *path, *template;
-	char			*cause, *cp;
+	char		       **argv, *cause, *cp;
-	int			 idx, last, detached, cwd, fd = -1;
+	int			 argc, idx, last, detached, cwd, fd = -1;
 	struct format_tree	*ft;
 	struct environ_entry	*envent;
 
@@ -84,10 +84,19 @@ cmd_new_window_exec(struct cmd *self, struct cmd_q *cmdq)
 	}
 	detached = args_has(args, 'd');
 
-	if (args->argc == 0)
+	if (args->argc == 0) {
 		cmd = options_get_string(&s->options, "default-command");
-	else
+		if (cmd != NULL && *cmd != '\0') {
-		cmd = args->argv[0];
+			argc = 1;
+			argv = (char**)&cmd;
+		} else {
+			argc = 0;
+			argv = NULL;
+		}
+	} else {
+		argc = args->argc;
+		argv = args->argv;
+	}
 
 	path = NULL;
 	if (cmdq->client != NULL && cmdq->client->session == NULL)
@@ -145,7 +154,8 @@ cmd_new_window_exec(struct cmd *self, struct cmd_q *cmdq)
 
 	if (idx == -1)
 		idx = -1 - options_get_number(&s->options, "base-index");
-	wl = session_new(s, args_get(args, 'n'), cmd, path, cwd, idx, &cause);
+	wl = session_new(s, args_get(args, 'n'), argc, argv, path, cwd, idx,
+		&cause);
 	if (wl == NULL) {
 		cmdq_error(cmdq, "create window failed: %s", cause);
 		free(cause);

cmd-respawn-pane.c

@@ -32,7 +32,7 @@ enum cmd_retval	 cmd_respawn_pane_exec(struct cmd *, struct cmd_q *);
 
 const struct cmd_entry cmd_respawn_pane_entry = {
 	"respawn-pane", "respawnp",
-	"kt:", 0, 1,
+	"kt:", 0, -1,
 	"[-k] " CMD_TARGET_PANE_USAGE " [command]",
 	0,
 	NULL,
@@ -48,7 +48,7 @@ cmd_respawn_pane_exec(struct cmd *self, struct cmd_q *cmdq)
 	struct window_pane	*wp;
 	struct session		*s;
 	struct environ		 env;
-	const char		*cmd, *path;
+	const char		*path;
 	char			*cause;
 	u_int			 idx;
 	struct environ_entry	*envent;
@@ -74,11 +74,6 @@ cmd_respawn_pane_exec(struct cmd *self, struct cmd_q *cmdq)
 	screen_reinit(&wp->base);
 	input_init(wp);
 
-	if (args->argc != 0)
-		cmd = args->argv[0];
-	else
-		cmd = NULL;
-
 	path = NULL;
 	if (cmdq->client != NULL && cmdq->client->session == NULL)
 		envent = environ_find(&cmdq->client->environ, "PATH");
@@ -87,8 +82,8 @@ cmd_respawn_pane_exec(struct cmd *self, struct cmd_q *cmdq)
 	if (envent != NULL)
 		path = envent->value;
 
-	if (window_pane_spawn(wp, cmd, path, NULL, -1, &env, s->tio,
+	if (window_pane_spawn(wp, args->argc, args->argv, path, NULL, -1, &env,
-	    &cause) != 0) {
+	    s->tio, &cause) != 0) {
 		cmdq_error(cmdq, "respawn pane failed: %s", cause);
 		free(cause);
 		environ_free(&env);

cmd-respawn-window.c

@@ -31,7 +31,7 @@ enum cmd_retval	 cmd_respawn_window_exec(struct cmd *, struct cmd_q *);
 
 const struct cmd_entry cmd_respawn_window_entry = {
 	"respawn-window", "respawnw",
-	"kt:", 0, 1,
+	"kt:", 0, -1,
 	"[-k] " CMD_TARGET_WINDOW_USAGE " [command]",
 	0,
 	NULL,
@@ -47,7 +47,7 @@ cmd_respawn_window_exec(struct cmd *self, struct cmd_q *cmdq)
 	struct window_pane	*wp;
 	struct session		*s;
 	struct environ		 env;
-	const char		*cmd, *path;
+	const char		*path;
 	char		 	*cause;
 	struct environ_entry	*envent;
 
@@ -76,10 +76,6 @@ cmd_respawn_window_exec(struct cmd *self, struct cmd_q *cmdq)
 	window_destroy_panes(w);
 	TAILQ_INSERT_HEAD(&w->panes, wp, entry);
 	window_pane_resize(wp, w->sx, w->sy);
-	if (args->argc != 0)
-		cmd = args->argv[0];
-	else
-		cmd = NULL;
 
 	path = NULL;
 	if (cmdq->client != NULL && cmdq->client->session == NULL)
@@ -89,8 +85,8 @@ cmd_respawn_window_exec(struct cmd *self, struct cmd_q *cmdq)
 	if (envent != NULL)
 		path = envent->value;
 
-	if (window_pane_spawn(wp, cmd, path, NULL, -1, &env, s->tio,
+	if (window_pane_spawn(wp, args->argc, args->argv, path, NULL, -1, &env,
-	    &cause) != 0) {
+	    s->tio, &cause) != 0) {
 		cmdq_error(cmdq, "respawn window failed: %s", cause);
 		free(cause);
 		environ_free(&env);

cmd-split-window.c

@@ -36,7 +36,7 @@ enum cmd_retval	 cmd_split_window_exec(struct cmd *, struct cmd_q *);
 
 const struct cmd_entry cmd_split_window_entry = {
 	"split-window", "splitw",
-	"c:dF:l:hp:Pt:v", 0, 1,
+	"c:dF:l:hp:Pt:v", 0, -1,
 	"[-dhvP] [-c start-directory] [-F format] [-p percentage|-l size] "
 	CMD_TARGET_PANE_USAGE " [command]",
 	0,
@@ -62,9 +62,9 @@ cmd_split_window_exec(struct cmd *self, struct cmd_q *cmdq)
 	struct window_pane	*wp, *new_wp = NULL;
 	struct environ		 env;
 	const char		*cmd, *path, *shell, *template;
-	char			*cause, *new_cause, *cp;
+	char		       **argv, *cause, *new_cause, *cp;
 	u_int			 hlimit;
-	int			 size, percentage, cwd, fd = -1;
+	int			 argc, size, percentage, cwd, fd = -1;
 	enum layout_type	 type;
 	struct layout_cell	*lc;
 	struct client		*c;
@@ -81,10 +81,19 @@ cmd_split_window_exec(struct cmd *self, struct cmd_q *cmdq)
 	environ_copy(&s->environ, &env);
 	server_fill_environ(s, &env);
 
-	if (args->argc == 0)
+	if (args->argc == 0) {
 		cmd = options_get_string(&s->options, "default-command");
-	else
+		if (cmd != NULL && *cmd != '\0') {
-		cmd = args->argv[0];
+			argc = 1;
+			argv = (char**)&cmd;
+		} else {
+			argc = 0;
+			argv = NULL;
+		}
+	} else {
+		argc = args->argc;
+		argv = args->argv;
+	}
 
 	if (args_has(args, 'c')) {
 		ft = format_create();
@@ -158,8 +167,8 @@ cmd_split_window_exec(struct cmd *self, struct cmd_q *cmdq)
 	if (envent != NULL)
 		path = envent->value;
 
-	if (window_pane_spawn(
+	if (window_pane_spawn(new_wp, argc, argv, path, shell, cwd, &env,
-	    new_wp, cmd, path, shell, cwd, &env, s->tio, &cause) != 0)
+	    s->tio, &cause) != 0)
 		goto error;
 	layout_assign_pane(lc, new_wp);
 

cmd.c

@@ -187,7 +187,7 @@ cmd_copy_argv(int argc, char **argv)
 
 	if (argc == 0)
 		return (NULL);
-	new_argv = xcalloc(argc, sizeof *new_argv);
+	new_argv = xcalloc(argc + 1, sizeof *new_argv);
 	for (i = 0; i < argc; i++) {
 		if (argv[i] != NULL)
 			new_argv[i] = xstrdup(argv[i]);
@@ -207,6 +207,32 @@ cmd_free_argv(int argc, char **argv)
 	free(argv);
 }
 
+char *
+cmd_stringify_argv(int argc, char **argv)
+{
+	char	*buf;
+	int	 i;
+	size_t	 len;
+
+	if (argc == 0)
+		return (xstrdup(""));
+
+	len = 0;
+	buf = NULL;
+
+	for (i = 0; i < argc; i++) {
+		len += strlen(argv[i]) + 1;
+		buf = xrealloc(buf, 1, len);
+
+		if (i == 0)
+			*buf = '\0';
+		else
+			strlcat(buf, " ", len);
+		strlcat(buf, argv[i], len);
+	}
+	return (buf);
+}
+
 struct cmd *
 cmd_parse(int argc, char **argv, const char *file, u_int line, char **cause)
 {

format.c

@@ -368,7 +368,7 @@ format_get_command(struct window_pane *wp)
 	cmd = get_proc_name(wp->fd, wp->tty);
 	if (cmd == NULL || *cmd == '\0') {
 		free(cmd);
-		cmd = xstrdup(wp->cmd);
+		cmd = cmd_stringify_argv(wp->argc, wp->argv);
 		if (cmd == NULL || *cmd == '\0') {
 			free(cmd);
 			cmd = xstrdup(wp->shell);
@@ -559,8 +559,10 @@ format_window_pane(struct format_tree *ft, struct window_pane *wp)
 	if (wp->tty != NULL)
 		format_add(ft, "pane_tty", "%s", wp->tty);
 	format_add(ft, "pane_pid", "%ld", (long) wp->pid);
-	if (wp->cmd != NULL)
+	if ((cmd = cmd_stringify_argv(wp->argc, wp->argv)) != NULL) {
-		format_add(ft, "pane_start_command", "%s", wp->cmd);
+		format_add(ft, "pane_start_command", "%s", cmd);
+		free(cmd);
+	}
 	if ((cmd = format_get_command(wp)) != NULL) {
 		format_add(ft, "pane_current_command", "%s", cmd);
 		free(cmd);

names.c

@@ -68,9 +68,15 @@ window_name_callback(unused int fd, unused short events, void *data)
 char *
 default_window_name(struct window *w)
 {
-	if (w->active->cmd != NULL && *w->active->cmd != '\0')
+	char    *cmd, *s;
-		return (parse_window_name(w->active->cmd));
+
-	return (parse_window_name(w->active->shell));
+	cmd = cmd_stringify_argv(w->active->argc, w->active->argv);
+	if (cmd != NULL && *cmd != '\0')
+		s = parse_window_name(cmd);
+	else
+		s = parse_window_name(w->active->shell);
+	free(cmd);
+	return (s);
 }
 
 char *

session.c

@@ -85,11 +85,12 @@ session_find_by_id(u_int id)
 
 /* Create a new session. */
 struct session *
-session_create(const char *name, const char *cmd, const char *path, int cwd,
+session_create(const char *name, int argc, char **argv, const char *path,
-    struct environ *env, struct termios *tio, int idx, u_int sx, u_int sy,
+    int cwd, struct environ *env, struct termios *tio, int idx, u_int sx,
-    char **cause)
+    u_int sy, char **cause)
 {
 	struct session	*s;
+	struct winlink	*wl;
 
 	s = xmalloc(sizeof *s);
 	s->references = 0;
@@ -132,8 +133,9 @@ session_create(const char *name, const char *cmd, const char *path, int cwd,
 	}
 	RB_INSERT(sessions, &sessions, s);
 
-	if (cmd != NULL) {
+	if (argc >= 0) {
-		if (session_new(s, NULL, cmd, path, cwd, idx, cause) == NULL) {
+		wl = session_new(s, NULL, argc, argv, path, cwd, idx, cause);
+		if (wl == NULL) {
 			session_destroy(s);
 			return (NULL);
 		}
@@ -227,7 +229,7 @@ session_previous_session(struct session *s)
 
 /* Create a new window on a session. */
 struct winlink *
-session_new(struct session *s, const char *name, const char *cmd,
+session_new(struct session *s, const char *name, int argc, char **argv,
     const char *path, int cwd, int idx, char **cause)
 {
 	struct window	*w;
@@ -251,8 +253,8 @@ session_new(struct session *s, const char *name, const char *cmd,
 		shell = _PATH_BSHELL;
 
 	hlimit = options_get_number(&s->options, "history-limit");
-	w = window_create(name, cmd, path, shell, cwd, &env, s->tio, s->sx,
+	w = window_create(name, argc, argv, path, shell, cwd, &env, s->tio,
-	    s->sy, hlimit, cause);
+	    s->sx, s->sy, hlimit, cause);
 	if (w == NULL) {
 		winlink_remove(&s->windows, wl);
 		environ_free(&env);

tmux.1

@@ -478,12 +478,37 @@ It may be used alone to target a pane or the window containing it.
 arguments are
 .Xr sh 1
 commands.
-These must be passed as a single item, which typically means quoting them, for
+This may be a single argument passed to the shell, for example:
-example:
 .Bd -literal -offset indent
 new-window 'vi /etc/passwd'
 .Ed
 .Pp
+Will run:
+.Bd -literal -offset indent
+/bin/sh -c 'vi /etc/passwd'
+.Ed
+.Pp
+Additionally, the
+.Ic new-window ,
+.Ic new-session ,
+.Ic split-window ,
+.Ic respawn-window
+and
+.Ic respawn-pane
+commands allow
+.Ar shell-command
+to be given as multiple arguments and executed directly (without
+.Ql sh -c ) .
+This can avoid issues with shell quoting.
+For example:
+.Bd -literal -offset indent
+$ tmux new-window vi /etc/passwd
+.Ed
+.Pp
+Will run
+.Xr vi 1
+directly without invoking the shell.
+.Pp
 .Ar command
 .Op Ar arguments
 refers to a

tmux.h

@@ -914,7 +914,8 @@ struct window_pane {
 #define PANE_RESIZE 0x8
 #define PANE_FOCUSPUSH 0x10
 
-	char		*cmd;
+	int		 argc;
+	char	       **argv;
 	char		*shell;
 	int		 cwd;
 
@@ -1750,6 +1751,7 @@ int		 cmd_pack_argv(int, char **, char *, size_t);
 int		 cmd_unpack_argv(char *, size_t, int, char ***);
 char	       **cmd_copy_argv(int, char **);
 void		 cmd_free_argv(int, char **);
+char		*cmd_stringify_argv(int, char **);
 struct cmd	*cmd_parse(int, char **, const char *, u_int, char **);
 size_t		 cmd_print(struct cmd *, char *, size_t);
 struct session	*cmd_current_session(struct cmd_q *, int);
@@ -2140,7 +2142,7 @@ void		 winlink_stack_remove(struct winlink_stack *, struct winlink *);
 int		 window_index(struct window *, u_int *);
 struct window	*window_find_by_id(u_int);
 struct window	*window_create1(u_int, u_int);
-struct window	*window_create(const char *, const char *, const char *,
+struct window	*window_create(const char *, int, char **, const char *,
 		     const char *, int, struct environ *, struct termios *,
 		     u_int, u_int, u_int, char **);
 void		 window_destroy(struct window *);
@@ -2166,7 +2168,7 @@ struct window_pane *window_pane_find_by_id(u_int);
 struct window_pane *window_pane_create(struct window *, u_int, u_int, u_int);
 void		 window_pane_destroy(struct window_pane *);
 void		 window_pane_timer_start(struct window_pane *);
-int		 window_pane_spawn(struct window_pane *, const char *,
+int		 window_pane_spawn(struct window_pane *, int, char **,
 		     const char *, const char *, int, struct environ *,
 		     struct termios *, char **);
 void		 window_pane_resize(struct window_pane *, u_int, u_int);
@@ -2304,18 +2306,18 @@ RB_PROTOTYPE(sessions, session, entry, session_cmp);
 int		 session_alive(struct session *);
 struct session	*session_find(const char *);
 struct session	*session_find_by_id(u_int);
-struct session	*session_create(const char *, const char *, const char *, int,
+struct session	*session_create(const char *, int, char **, const char *,
-		     struct environ *, struct termios *, int, u_int, u_int,
+		     int, struct environ *, struct termios *, int, u_int,
-		     char **);
+		     u_int, char **);
 void		 session_destroy(struct session *);
 int		 session_check_name(const char *);
 void		 session_update_activity(struct session *);
 struct session	*session_next_session(struct session *);
 struct session	*session_previous_session(struct session *);
-struct winlink	*session_new(struct session *, const char *, const char *,
+struct winlink	*session_new(struct session *, const char *, int, char **,
 		     const char *, int, int, char **);
-struct winlink	*session_attach(
+struct winlink	*session_attach(struct session *, struct window *, int,
-		     struct session *, struct window *, int, char **);
+		     char **);
 int		 session_detach(struct session *, struct winlink *);
 struct winlink	*session_has(struct session *, struct window *);
 int		 session_next(struct session *, int);

window.c

@@ -307,7 +307,7 @@ window_create1(u_int sx, u_int sy)
 }
 
 struct window *
-window_create(const char *name, const char *cmd, const char *path,
+window_create(const char *name, int argc, char **argv, const char *path,
     const char *shell, int cwd, struct environ *env, struct termios *tio,
     u_int sx, u_int sy, u_int hlimit, char **cause)
 {
@@ -318,7 +318,7 @@ window_create(const char *name, const char *cmd, const char *path,
 	wp = window_add_pane(w, hlimit);
 	layout_init(w, wp);
 
-	if (window_pane_spawn(wp, cmd, path, shell, cwd, env, tio,
+	if (window_pane_spawn(wp, argc, argv, path, shell, cwd, env, tio,
 	    cause) != 0) {
 		window_destroy(w);
 		return (NULL);
@@ -678,7 +678,8 @@ window_pane_create(struct window *w, u_int sx, u_int sy, u_int hlimit)
 	wp->id = next_window_pane_id++;
 	RB_INSERT(window_pane_tree, &all_window_panes, wp);
 
-	wp->cmd = NULL;
+	wp->argc = 0;
+	wp->argv = NULL;
 	wp->shell = NULL;
 	wp->cwd = -1;
 
@@ -737,27 +738,29 @@ window_pane_destroy(struct window_pane *wp)
 
 	close(wp->cwd);
 	free(wp->shell);
-	free(wp->cmd);
+	cmd_free_argv(wp->argc, wp->argv);
 	free(wp);
 }
 
 int
-window_pane_spawn(struct window_pane *wp, const char *cmd, const char *path,
+window_pane_spawn(struct window_pane *wp, int argc, char **argv,
-    const char *shell, int cwd, struct environ *env, struct termios *tio,
+    const char *path, const char *shell, int cwd, struct environ *env,
-    char **cause)
+    struct termios *tio, char **cause)
 {
 	struct winsize	 ws;
-	char		*argv0, paneid[16];
+	char		*argv0, *cmd, **argvp, paneid[16];
-	const char	*ptr;
+	const char	*ptr, *first;
 	struct termios	 tio2;
+	int		 i;
 
 	if (wp->fd != -1) {
 		bufferevent_free(wp->event);
 		close(wp->fd);
 	}
-	if (cmd != NULL) {
+	if (argc > 0) {
-		free(wp->cmd);
+		cmd_free_argv(wp->argc, wp->argv);
-		wp->cmd = xstrdup(cmd);
+		wp->argc = argc;
+		wp->argv = cmd_copy_argv(argc, argv);
 	}
 	if (shell != NULL) {
 		free(wp->shell);
@@ -768,7 +771,10 @@ window_pane_spawn(struct window_pane *wp, const char *cmd, const char *path,
 		wp->cwd = dup(cwd);
 	}
 
-	log_debug("spawn: %s -- %s", wp->shell, wp->cmd);
+	cmd = cmd_stringify_argv(wp->argc, wp->argv);
+	log_debug("spawn: %s -- %s", wp->shell, cmd);
+	for (i = 0; i < wp->argc; i++)
+		log_debug("spawn: argv[%d] = %s", i, wp->argv[i]);
 
 	memset(&ws, 0, sizeof ws);
 	ws.ws_col = screen_size_x(&wp->base);
@@ -778,6 +784,7 @@ window_pane_spawn(struct window_pane *wp, const char *cmd, const char *path,
 	case -1:
 		wp->fd = -1;
 		xasprintf(cause, "%s: %s", cmd, strerror(errno));
+		free(cmd);
 		return (-1);
 	case 0:
 		if (fchdir(wp->cwd) != 0)
@@ -805,31 +812,42 @@ window_pane_spawn(struct window_pane *wp, const char *cmd, const char *path,
 		setenv("SHELL", wp->shell, 1);
 		ptr = strrchr(wp->shell, '/');
 
-		if (*wp->cmd != '\0') {
+		/*
-			/* Use the command. */
+		 * If given one argument, assume it should be passed to sh -c;
+		 * with more than one argument, use execvp(). If there is no
+		 * arguments, create a login shell.
+		 */
+		if (wp->argc > 0) {
+			if (wp->argc != 1) {
+				/* Copy to ensure argv ends in NULL. */
+				argvp = cmd_copy_argv(wp->argc, wp->argv);
+				execvp(argvp[0], argvp);
+				fatal("execvp failed");
+			}
+			first = wp->argv[0];
+
 			if (ptr != NULL && *(ptr + 1) != '\0')
 				xasprintf(&argv0, "%s", ptr + 1);
 			else
 				xasprintf(&argv0, "%s", wp->shell);
-			execl(wp->shell, argv0, "-c", wp->cmd, (char *) NULL);
+			execl(wp->shell, argv0, "-c", first, (char *)NULL);
 			fatal("execl failed");
 		}
-
-		/* No command; fork a login shell. */
 		if (ptr != NULL && *(ptr + 1) != '\0')
 			xasprintf(&argv0, "-%s", ptr + 1);
 		else
 			xasprintf(&argv0, "-%s", wp->shell);
-		execl(wp->shell, argv0, (char *) NULL);
+		execl(wp->shell, argv0, (char *)NULL);
 		fatal("execl failed");
 	}
 
 	setblocking(wp->fd, 0);
 
-	wp->event = bufferevent_new(wp->fd,
+	wp->event = bufferevent_new(wp->fd, window_pane_read_callback, NULL,
-	    window_pane_read_callback, NULL, window_pane_error_callback, wp);
+	    window_pane_error_callback, wp);
 	bufferevent_enable(wp->event, EV_READ|EV_WRITE);
 
+	free(cmd);
 	return (0);
 }