Returning error code from DNR script (in Unix)

System

I know this has been discussed here: thread but I need to implement this in Unix shell rather than Perl and I'm no Unix shell expert. Does anyone have any shell script interpretation of this Perl code for a DNR script to return a response code of -2? Also, in Unix, how does one determine if a DNR DD deployment has failed?

... use constant SUCCESS => 0; use constant FAILURE => 1;  my $status = SUCCESS; eval {main();}; if ($@) {    log_it("Error Executing Deployment DNR Task: $@\n");    $status = FAILURE; }  # Let OpenDeploy know if processing failed print qq(\n) if($status); exit($status); ... sub main {...}

**** - I can't format this code properly...