#./prefork.pl &
# ps -ef | grep prefork.pl
root     22626   947  0 15:34 pts/3    ./prefork.pl
root     22627 22626  0 15:34 pts/3    ./prefork.pl
root     22628 22626  0 15:34 pts/3    ./prefork.pl
#kill 22626
#ps -ef | grep prefork
root     22627     1  0 15:34 pts/3  ./prefork.pl
root     22628     1  0 15:34 pts/3  ./prefork.pl