use IPC::Exe;  ## exports bg() & exe()

my $parallel_handle = bg sub {
                             my ($payload) = @_;

                             ## Run one after another, but parallel wrt to parent process ##

                             &{ exe 'convert.sh', $payload, @ARGV };
                             die "Couldn't launch: $!/$?" if $! = $? >> 8;

                             &{ exe 'load_db.sh', $payload };
                             warn "Couldn't launch: $!/$?" if $! = $? >> 8;
                         };
my $payload = "ha ha!";
print "Background PID: ", $parallel_handle->($payload), "\n";