我的/etc/rc.local脚本中有一个命令，它应该在启动期间启动Tiny Tiny RSS的更新守护程序，但在启动期间不执行该脚本。为什么？
整个 /etc/rc.local 文件：
#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.
/sbin/start-stop-daemon -b -c www-data:www-data -S -x /usr/bin/php /var/www/ttrss/update_daemon2.php -- -quiet …