On 2023-10-12 02:04, Jeff King wrote:
On Wed, Oct 11, 2023 at 03:23:20PM -0700, Junio C Hamano wrote:
Christoph Anton Mitterer <calestyo@xxxxxxxxxxxx> writes:
> But I still don't get from that why X would be needed?
>
> My less manpage documents it as:
>> -X or --no‐init
>> Disables sending the termcap initialization and deinitialization
>> strings to the terminal. This is sometimes desirable if the
>> deinitialization string does something unnecessary, like clearing
>> the screen.
>
> Is it to avoid clearing the screen?
I think that was the reason we added it back in 2005. In any case,
asking "why" is not a useful use of anybody's time, because it is
very unlikely to change in the official version we ship, and because
it is so easy for any individual who does not like it to drop by
exporting the $LESS environment variable.
I agree it is probably not worth changing now, but I think the history
here is a little interesting.
Yes, I think "X" was added because less would clear the screen after
exiting, and with "F" this meant you'd see nothing. Here's a thread
from
the same time period discussing it:
https://lore.kernel.org/git/cc723f590610210623sbee2075i5f2fd441cceb84ae@xxxxxxxxxxxxxx/
But I also think this was a pretty well-known annoyance with "less"
back
then.
However, I can't seem to reproduce it now! Digging into the history and
the changelog, this note is in "changes between less versions 487 and
530":
Don't output terminal init sequence if using -F and file fits on one
screen.
So it seems like the problem has been fixed inside less for recent
versions. And in theory we _could_ drop "-X" if it is causing problems.
That version of less is ~5 years old. It does seem a little premature
to
assume everybody has it. And as you say, if there are people who really
care about their LESS options, it is easy for them to override it.
Thanks for this detailed analysis!
It's important to keep in mind that removing "-X" and leaving "-F" would
introduce an inconsistency in the displaying of outputs, by having the
long outputs disappear after exiting the pager manually, and by having
the short outputs remain displayed after the pager exits on its own.
On the other hand, removing both "-X" and "-F" would make people even
more annoyed by requiring them to exit the pager manually even for short
outputs.
Quite frankly, "-FRX" is a just fine set of defaults.
