The native status returned by the last pipe close, backtick (``) command, successful call to wait() or waitpid(), or from the system() operator. On POSIX-like systems this value can be decoded with the WIFEXITED, WEXITSTATUS, WIFSIGNALED, WTERMSIG, WIFSTOPPED, and WSTOPSIG functions provided by the POSIX module.
Under VMS this reflects the actual VMS exit status; i.e. it is the same as $? when the pragma use vmsish 'status' is in effect.
This variable was added in Perl v5.10.0.