Symbolic linked files are commonly used in Linux system. For example some service inital scripts are stored in /etc/init.d and linked to /etc/rc0.d, /etc/rc1.d, /etc/rc2.d, /etc/rc3.d, /etc/rc4.d, /etc/rc5.d and /etc/rc6.d, so that the system is able to control related services in different runlevel. (function(d, [...]