| hand waving here
my $a=1;
my $b=2;

if ( fork() ){
         # becomes 2 for the parent
         $a++;
} else { 
         # becomes 3 for the child
         $a=3;
}
| etc.

##</code><code>##

       SIGUSR1     30    user defined signal 1
       SIGUSR2     31    user defined signal 2


##</code><code>##

       SIGUSR1   30,10,16    Term    User-defined signal 1
       SIGUSR2   31,12,17    Term    User-defined signal 2

##</code><code>##

# handwaving
if ( fork() ){
     # this is the parent 
     $SIG{USR1)=\&parentHandler;
} else { 
     # child
     $SIG{USR1} =\&childHandler;
}