Re: [PATCH] Enable pager by default

[Michael Chang <MChang@suse.com>]

On Thu, Oct 24, 2019 at 04:39:09PM +0200, Daniel Kiper wrote:
> On Thu, Oct 24, 2019 at 06:54:53AM +0000, Michael Chang wrote:
> > On Tue, Oct 22, 2019 at 04:04:28PM +0200, Daniel Kiper wrote:
> > > On Tue, Oct 22, 2019 at 10:30:20AM +0200, Javier Martinez Canillas wrote:
> > > > Hello Daniel,
> > > >
> > > > On 10/21/19 4:56 PM, Daniel Kiper wrote:
> > > > > On Fri, Oct 18, 2019 at 02:43:18PM +0200, Javier Martinez Canillas wrote:
> > > > >> From: Peter Jones <pjones@redhat.com>
> > > > >>
> > > > >> When user enters into the GRUB shell and tries to use help command, lot of
> > > > >> information is scrolled out of screen and the user doesn't have chance to
> > > > >> read it. Also, there isn't any information about 'set pager=1' at the end
> > > > >> of the help output, to tell the user how scrolling could be enabled.
> > > > >>
> > > > >> So just enable pager by default which leads to a much better experience.
> > > > >
> > > > > Hmmm... What will happen if a command produce tons of output during boot
> > > > > process? I am afraid that it will hang indefinitely waiting for an user
> > > > > input. This should not happen. So, I tend to agree that current help
> > > > > command behavior is annoying but I do not like the solution.
> > > >
> > > > Ok. I'll then explore having a paginated output only for the help command
> > > > instead of globally enabling it by default.
> > >
> > > Great! Though I would think about something which can be used also in
> > > other commands producing a lot of output. Maybe we should introduce "-p"
> > > (pause) command line option for such commands. And I am not against
> > > using existing code to do a pause. We just have to do it carefully.
> >
> > I'd like to add option to the list, which is grub could provide the
> > information to have the commands able to tell they are executed in
> > shell's interactive (aka command-line) or batch mode. After they could
> > turn on/off paginated output according to the shell mode they are with.
> 
> Sounds interesting. However, I would go further. If pager == 1 and we are
> in batch mode then paging is inactive. If pager == 2 and we are in batch
> mode then paging is active. If we are in interactive mode then if
> pager != 0 then paging is active.

I agree completely. In this way we no longer have to worry about setting
page=1 would disrupt boot process as some command output could go overly
log and at the same time setting page=2 could enforce paginated output
everywhere, like what is working now. :)

Thanks,
Michael

> 
> Daniel