Jim Meyering <jim@meyering.net> writes:

> Great! Thank you.
>
>> but it will need a change in the code as well, since
>> the signals are installed only when outputting to a tty:
> ...
>> -  if (output_is_tty)
>> +  if (output_is_tty || getenv ("DIFF_INSTALL_SIGNALS"))
>>      install_signal_handlers ();
>
> However, we try very hard to avoid making tools depend on
> environment variable settings more than they already do,
> so how about a hidden, three-hyphen option, say,
> ---presume-output-tty, analogous to rm's ---presume-input-tty?

I have added a test that uses the new option ---presume-output-tty.