my $rv = system('perl -e "exit(123)"');

die("Unable to launch command: $!\n")
   if $rv == -1;

die("Child died with signal ", ($rv & 127), "\n")
   if $rv & 127;

die("Child exited with value ", ($rv >> 8), "\n")
   if $rv >> 8;

print("Child exited successfully\n");

##</code><code>##

Child exited with value 123