$  false
>= 1

# no comment is allowed at start of file, because of the first input's < delimiter being optional.

$  echo foo
foo

$  cat --unknown-option
>2 /option/
>= 1

# slashes in a regexp matcher must be backslash-escaped
$  echo 2000/1/2
> /2000\/1\/2/

# comment at end of file