use POSIX;
$SIG{CHLD} = sub {
    while( ( my $pid = waitpid(-1, POSIX::WNOHANG()) ) > 0 ){
        ## cleanup code...
        ## you probably should save the forked
        ## pids and make sure that the result of
        ## waitpid is indeed your child
    }
}

foreach my $nod ( @devices ) {
   my $pid = fork();
   if( !$pid ) {
      ## child...
   }
}