Re: Is there some syntax for executing {} for 1..Inf?

[Ævar Arnfjörð Bjarmason]

On Thu, Dec 7, 2017 at 9:33 PM, Ævar Arnfjörð Bjarmason
<avarab@gmail.com> wrote:
> On Thu, Dec 7, 2017 at 1:35 PM, Martin Møller Skarbiniks Pedersen
> <traxplayer@gmail.com> wrote:
>> On 7 December 2017 at 13:28, Martin Møller Skarbiniks Pedersen
>> <traxplayer@gmail.com> wrote:
>>>
>>> On 7 December 2017 at 00:37, Ævar Arnfjörð Bjarmason <avarab@gmail.com>
>>> wrote:
>>>>
>>>> I recently had a use-case for:
>>>>
>>>>     parallel 'cmd {}' ::: {1..Inf}
>>>>
>>>
>>> Maybe something like this:
>>>
>>> yes | cat -n | cut -f1 | parallel ' cmd {} '
>>>
>>
>> There are of course many variants but if you prefore perl:
>> yes |  perl -ne ' print "$.\n" '
>
> Thanks. That's very clever, I didn't think of that.
>
> I have no idea why and don't have time to reproduce it, but if I do:
>
>     yes | cat -n ... parallel --halt ...
>
> Inside a /bin/sh script the yes continues trying to write to the
> broken pipe ven though parallel has exited, although I couldn't
> produce it interactively. So I went with this:
>
>     perl -E '1 while say ++$_' | parallel --halt ...
>
> Which also counts up to infinity, but stops as soon as the write()
> call to a broken pipe fails.

The root cause of this is that signals are inherited from parent
processes, and the parent was setting SIGPIPE to SIG_IGN.