For example, look at the following output, which is a detective-work
of finding the real program that is the mail server on my system
(note: long lines were broken down, so they can fit the screen):
[choo@simey ~]$ ls -l /usr/sbin/sendmail
lrwxrwxrwx 1 root root 21 Aug 15 2002
/usr/sbin/sendmail -> /etc/alternatives/mta
[choo@simey ~]$ ls -l /etc/alternatives/mta
lrwxrwxrwx 1 root root 27 Aug 15 2002
/etc/alternatives/mta -> /usr/sbin/sendmail.sendmail
[choo@simey ~]$ ls -l /usr/sbin/sendmail.sendmail
-r-sr-xr-x 1 root root 451280 Apr 8 2002
/usr/sbin/sendmail.sendmail