I guess if you wanted to check if $garbage is a valid exe before executing it you could do something like the following. I'm not sure what the behavior is on 5.002 with File::Spec - can probably replace that with split(/:/,$ENV{'PATH'});

use File::Spec;

sub valid_exe {
  my $exe = shift;
  for my $dir ( File::Spec->path() ) {
    my $f = File::Spec->catfile($dir,$exe);
    if( -e $f && -x $f ) { # it is a valid exe
     return 1;
     }
  }
  return 0;
}
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Essentially what which will do for you, your call if it is cleaner.