diff --git a/cmd-join-pane.c b/cmd-join-pane.c
index 6b6421fa..2fa2561f 100644
--- a/cmd-join-pane.c
+++ b/cmd-join-pane.c
@@ -118,7 +118,7 @@ cmd_join_pane_exec(struct cmd *self, struct cmdq_item *item)
 		size = args_percentage_and_expand(args, 'l', 0, INT_MAX, curval,
 			   item, &cause);
 	} else if (args_has(args, 'p')) {
-		size = args_strtonum_and_expand(args, 'l', 0, 100, item,
+		size = args_strtonum_and_expand(args, 'p', 0, 100, item,
 			   &cause);
 		if (cause == NULL)
 			size = curval * size / 100;
diff --git a/cmd-pipe-pane.c b/cmd-pipe-pane.c
index a2f8df1b..844b8b85 100644
--- a/cmd-pipe-pane.c
+++ b/cmd-pipe-pane.c
@@ -128,6 +128,8 @@ cmd_pipe_pane_exec(struct cmd *self, struct cmdq_item *item)
 		sigprocmask(SIG_SETMASK, &oldset, NULL);
 		cmdq_error(item, "fork error: %s", strerror(errno));
 
+		close(pipe_fd[0]);
+		close(pipe_fd[1]);
 		free(cmd);
 		return (CMD_RETURN_ERROR);
 	case 0:
diff --git a/cmd-run-shell.c b/cmd-run-shell.c
index 045f551e..a9f1c1fe 100644
--- a/cmd-run-shell.c
+++ b/cmd-run-shell.c
@@ -198,8 +198,17 @@ cmd_run_shell_timer(__unused int fd, __unused short events, void* arg)
 		}
 		if (job_run(cmd, 0, NULL, NULL, cdata->s, cdata->cwd, NULL,
 		    cmd_run_shell_callback, cmd_run_shell_free, cdata,
-		    cdata->flags, -1, -1) == NULL)
+		    cdata->flags, -1, -1) == NULL) {
+			if (cdata->item == NULL)
+				status_message_set(c, -1, 1, 0, 0,
+				    "failed to run command: %s", cmd);
+			else {
+				cmdq_error(cdata->item,
+				    "failed to run command: %s", cmd);
+				cmdq_continue(cdata->item);
+			}
 			cmd_run_shell_free(cdata);
+		}
 		return;
 	}
 
diff --git a/paste.c b/paste.c
index 7eda6ada..6461d9ba 100644
--- a/paste.c
+++ b/paste.c
@@ -204,6 +204,7 @@ int
 paste_rename(const char *oldname, const char *newname, char **cause)
 {
 	struct paste_buffer	*pb, *pb_new;
+	char			*name;
 
 	if (cause != NULL)
 		*cause = NULL;
@@ -219,23 +220,33 @@ paste_rename(const char *oldname, const char *newname, char **cause)
 		return (-1);
 	}
 
+	name = clean_name(newname, "");
+	if (name == NULL) {
+		if (cause != NULL)
+			xasprintf(cause, "invalid buffer name: %s", newname);
+		return (-1);
+	}
+
 	pb = paste_get_name(oldname);
 	if (pb == NULL) {
 		if (cause != NULL)
 			xasprintf(cause, "no buffer %s", oldname);
+		free(name);
 		return (-1);
 	}
 
-	pb_new = paste_get_name(newname);
-	if (pb_new == pb)
+	pb_new = paste_get_name(name);
+	if (pb_new == pb) {
+		free(name);
 		return (0);
+	}
 	if (pb_new != NULL)
 		paste_free(pb_new);
 
 	RB_REMOVE(paste_name_tree, &paste_by_name, pb);
 
 	free(pb->name);
-	pb->name = xstrdup(newname);
+	pb->name = name;
 
 	if (pb->automatic)
 		paste_num_automatic--;
@@ -244,7 +255,7 @@ paste_rename(const char *oldname, const char *newname, char **cause)
 	RB_INSERT(paste_name_tree, &paste_by_name, pb);
 
 	notify_paste_buffer(oldname, 1);
-	notify_paste_buffer(newname, 0);
+	notify_paste_buffer(pb->name, 0);
 
 	return (0);
 }
@@ -257,6 +268,7 @@ int
 paste_set(char *data, size_t size, const char *name, char **cause)
 {
 	struct paste_buffer	*pb, *old;
+	char			*newname;
 
 	if (cause != NULL)
 		*cause = NULL;
@@ -276,9 +288,16 @@ paste_set(char *data, size_t size, const char *name, char **cause)
 		return (-1);
 	}
 
+	newname = clean_name(name, "");
+	if (newname == NULL) {
+		if (cause != NULL)
+			xasprintf(cause, "invalid buffer name: %s", name);
+		return (-1);
+	}
+
 	pb = xmalloc(sizeof *pb);
 
-	pb->name = xstrdup(name);
+	pb->name = newname;
 
 	pb->data = data;
 	pb->size = size;
@@ -288,13 +307,13 @@ paste_set(char *data, size_t size, const char *name, char **cause)
 
 	pb->created = time(NULL);
 
-	if ((old = paste_get_name(name)) != NULL)
+	if ((old = paste_get_name(pb->name)) != NULL)
 		paste_free(old);
 
 	RB_INSERT(paste_name_tree, &paste_by_name, pb);
 	RB_INSERT(paste_time_tree, &paste_by_time, pb);
 
-	notify_paste_buffer(name, 0);
+	notify_paste_buffer(pb->name, 0);
 
 	return (0);
 }
diff --git a/window-copy.c b/window-copy.c
index ac89dc56..0b6bf69a 100644
--- a/window-copy.c
+++ b/window-copy.c
@@ -5171,7 +5171,8 @@ window_copy_pipe_run(struct window_mode_entry *wme, struct session *s,
 	if (cmd != NULL && *cmd != '\0') {
 		job = job_run(cmd, 0, NULL, NULL, s, NULL, NULL, NULL, NULL,
 		    NULL, JOB_NOWAIT, -1, -1);
-		bufferevent_write(job_get_event(job), buf, *len);
+		if (job != NULL)
+			bufferevent_write(job_get_event(job), buf, *len);
 	}
 	return (buf);
 }