% perldoc -q rand
Found in
     /home/columbia3/gclib/pkg/perl/lib/5.8.0/pod/perlfaq4.pod
     Why aren't my random numbers random?

             If you're using a version of Perl before 5.004, you
             must call "srand" once at the start of your program
             to seed the random number generator.  5.004 and
             later automatically call "srand" at the beginning.
             Don't call "srand" more than once--you make your
             numbers less random, rather than more.