$ perl -MErrno=ENOENT -le'
   $found = -e shift;
   die("stat: $!\n") if !defined($found) && $! != ENOENT;
   print($found ? "found" : "not found");
' foo/bar
not found

$ touch foo/bar

$ perl -MErrno=ENOENT -le'
   $found = -e shift;
   die("stat: $!\n") if !defined($found) && $! != ENOENT;
   print($found ? "found" : "not found");
' foo/bar
found

$ chmod a-x foo

$ perl -MErrno=ENOENT -le'
   $found = -e shift;
   die("stat: $!\n") if !defined($found) && $! != ENOENT;
   print($found ? "found" : "not found");
' foo/bar
stat: Permission denied