Perl Programming/Keywords/srand

The srand keyword
The srand function sets and returns the random number seed for the rand operator so that it can produce a different sequence of random numbers.

srand is called implicitly when rand is called, but can be called explicitly to generate random numbers for test purposes with the same seed (see below).

Please do not call srand by the same more than once without an EXPRESSION after it, as the random number generation will lose randomness.