diff --git a/client.c b/client.c
index 90b1371c..f94ce996 100644
--- a/client.c
+++ b/client.c
@@ -252,16 +252,13 @@ client_main(struct event_base *base, int argc, char **argv, int flags,
 		 * flag.
 		 */
 		cmdlist = cmd_list_parse(argc, argv, NULL, 0, &cause);
-		if (cmdlist == NULL) {
-			fprintf(stderr, "%s\n", cause);
-			return (1);
+		if (cmdlist != NULL) {
+			TAILQ_FOREACH(cmd, &cmdlist->list, qentry) {
+				if (cmd->entry->flags & CMD_STARTSERVER)
+					cmdflags |= CMD_STARTSERVER;
+			}
+			cmd_list_free(cmdlist);
 		}
-		cmdflags &= ~CMD_STARTSERVER;
-		TAILQ_FOREACH(cmd, &cmdlist->list, qentry) {
-			if (cmd->entry->flags & CMD_STARTSERVER)
-				cmdflags |= CMD_STARTSERVER;
-		}
-		cmd_list_free(cmdlist);
 	}
 
 	/* Create client process structure (starts logging). */
diff --git a/cmd-string.c b/cmd-string.c
index 1b96b280..822d35b5 100644
--- a/cmd-string.c
+++ b/cmd-string.c
@@ -54,17 +54,15 @@ cmd_string_ungetc(size_t *p)
 	(*p)--;
 }
 
-struct cmd_list *
-cmd_string_parse(const char *s, const char *file, u_int line, char **cause)
+int
+cmd_string_split(const char *s, int *rargc, char ***rargv)
 {
-	size_t		  p = 0;
-	int		  ch, i, argc = 0;
-	char		**argv = NULL, *buf = NULL, *t;
-	const char	 *whitespace, *equals;
-	size_t		  len = 0;
-	struct cmd_list	 *cmdlist = NULL;
+	size_t		p = 0;
+	int		ch, argc = 0, append = 0;
+	char	      **argv = NULL, *buf = NULL, *t;
+	const char     *whitespace, *equals;
+	size_t		len = 0;
 
-	*cause = NULL;
 	for (;;) {
 		ch = cmd_string_getc(s, &p);
 		switch (ch) {
@@ -115,43 +113,67 @@ cmd_string_parse(const char *s, const char *file, u_int line, char **cause)
 				argc--;
 				memmove(argv, argv + 1, argc * (sizeof *argv));
 			}
-			if (argc == 0)
-				goto out;
-
-			cmdlist = cmd_list_parse(argc, argv, file, line, cause);
-			goto out;
+			goto done;
 		case '~':
-			if (buf == NULL) {
-				t = cmd_string_expand_tilde(s, &p);
-				if (t == NULL)
-					goto error;
-				cmd_string_copy(&buf, t, &len);
+			if (buf != NULL) {
+				append = 1;
 				break;
 			}
-			/* FALLTHROUGH */
-		default:
-			if (len >= SIZE_MAX - 2)
+			t = cmd_string_expand_tilde(s, &p);
+			if (t == NULL)
 				goto error;
-
-			buf = xrealloc(buf, len + 1);
-			buf[len++] = ch;
+			cmd_string_copy(&buf, t, &len);
+			break;
+		default:
+			append = 1;
 			break;
 		}
+		if (append) {
+			if (len >= SIZE_MAX - 2)
+				goto error;
+			buf = xrealloc(buf, len + 1);
+			buf[len++] = ch;
+		}
+		append = 0;
 	}
 
+done:
+	*rargc = argc;
+	*rargv = argv;
+
+	free(buf);
+	return (0);
+
+error:
+	if (argv != NULL)
+		cmd_free_argv(argc, argv);
+	free(buf);
+	return (-1);
+}
+
+struct cmd_list *
+cmd_string_parse(const char *s, const char *file, u_int line, char **cause)
+{
+	struct cmd_list	 *cmdlist = NULL;
+	int		  argc;
+	char		**argv;
+
+	*cause = NULL;
+	if (cmd_string_split(s, &argc, &argv) != 0)
+		goto error;
+	if (argc != 0) {
+		cmdlist = cmd_list_parse(argc, argv, file, line, cause);
+		if (cmdlist == NULL) {
+			cmd_free_argv(argc, argv);
+			goto error;
+		}
+	}
+	cmd_free_argv(argc, argv);
+	return (cmdlist);
+
 error:
 	xasprintf(cause, "invalid or unknown command: %s", s);
-
-out:
-	free(buf);
-
-	if (argv != NULL) {
-		for (i = 0; i < argc; i++)
-			free(argv[i]);
-		free(argv);
-	}
-
-	return (cmdlist);
+	return (NULL);
 }
 
 static void
diff --git a/key-bindings.c b/key-bindings.c
index 65cc9b10..4cbb34ec 100644
--- a/key-bindings.c
+++ b/key-bindings.c
@@ -383,7 +383,7 @@ key_bindings_init(void)
 	for (i = 0; i < nitems(defaults); i++) {
 		cmdlist = cmd_string_parse(defaults[i], "<default>", i, &cause);
 		if (cmdlist == NULL)
-			fatalx("bad default key");
+			fatalx("bad default key: %s", defaults[i]);
 		cmdq_append(NULL, cmdq_get_command(cmdlist, NULL, NULL, 0));
 		cmd_list_free(cmdlist);
 	}
diff --git a/pty.c b/pty.c
index 05a02ef0..39794afc 100644
--- a/pty.c
+++ b/pty.c
@@ -45,7 +45,7 @@ pty_fork(int ptmfd, int *fd, char *name, size_t namelen, struct winsize *ws)
 	struct ptmget	ptm;
 	pid_t		pid;
 
-	if ((ioctl(ptmfd, PTMGET, &ptm) == -1))
+	if (ioctl(ptmfd, PTMGET, &ptm) == -1)
 		return (-1);
 
 	strlcpy(name, ptm.sn, namelen);
diff --git a/tmux.1 b/tmux.1
index b641909f..61396fbd 100644
--- a/tmux.1
+++ b/tmux.1
@@ -2410,6 +2410,30 @@ Available server options are:
 Set the number of buffers; as new buffers are added to the top of the stack,
 old ones are removed from the bottom if necessary to maintain this maximum
 length.
+.It Xo Ic command-alias[]
+.Ar name=value
+.Xc
+This is an array of custom aliases for commands.
+If an unknown command matches
+.Ar name ,
+it is replaced with
+.Ar value .
+For example, after:
+.Pp
+.Dl set -s command-alias[2] zoom='resize-pane -Z'
+.Pp
+Using:
+.Pp
+.Dl zoom -t:.1
+.Pp
+Is equivalent to:
+.Pp
+.Dl resize-pane -Z -t:.1
+.Pp
+Note that aliases are expanded when a command is parsed rather than when it is
+executed, so binding an alias with
+.Ic bind-key
+will bind the expanded form.
 .It Ic default-terminal Ar terminal
 Set the default terminal for new windows created in this session - the
 default value of the
diff --git a/tmux.h b/tmux.h
index 58fe992b..20ec044a 100644
--- a/tmux.h
+++ b/tmux.h
@@ -1828,6 +1828,7 @@ void printflike(2, 3) cmdq_print(struct cmdq_item *, const char *, ...);
 void printflike(2, 3) cmdq_error(struct cmdq_item *, const char *, ...);
 
 /* cmd-string.c */
+int		 cmd_string_split(const char *, int *, char ***);
 struct cmd_list	*cmd_string_parse(const char *, const char *, u_int, char **);
 
 /* cmd-wait-for.c */