#!/usr/bin/perl

use strict ;
use warnings ;

use Carp ;

# some code here

sub check_cmd {
  my %parms = @_ ;

  croak "No commands" unless
    exists $parms{cmd} and ref($parms{cmd}) eq 'ARRAY' ;

  my @cmd = @{$parms{cmd}} ;

  $parms{onerror} = 'croak' unless exists $parms{onerror} ;
  $parms{onerror} =  lc $parms{onerror} ;
  $parms{onerror} = 'croak' unless $parms{onerror} =~ /^(croak|carp|none)$/ ;

  $parms{errormsg} = "@cmd failed" unless exists $parms{errormsg} ;

  my $result = system(@cmd) ;
  unless ($result == 0) {
    print STDERR $parms{errormsg} ;
    croak report_error($?,$!) if $parms{onerror} eq 'croak' ;
    if ($parms{onerror} eq 'carp') {
      carp  report_error($?,$!) ;
      print STDERR "Press ENTER" ;
      scalar <STDIN> ;
    }
  }

  return $result >> 8 ; # exit value
}

sub report_error {
  my ($syserr,$message) = @_ ;
  my $signal    = $syserr & 127 ;
  my $exitvalue = $syserr >> 8 ;
  my $error ;

  if ($syserr == -1) {
    $error = "failed to execute: $message" ;
  } elsif ($signal) {
    $error = "program died with signal $signal" ;
  }

  return $error ;
}