distinguish q & Q, let latter exit without clearing screen

[jimc]

less has -XF options (iirc) that suppress clearing of screen on exit.
However, it is inconvenient to choose that before starting the browse.

ISTM it would be easy to assign different exit behavior (already possible)
to some of the :q command variations. My 1st try would prolly be to
assert those --options just before exit, but thats pure WAG.

[gwsw]

The -X flag doesn't specifically suppress clearing the screen, it suppresses (both) the terminal init and deinit sequences. Normally the init sequence is sent when less starts and the deinit is sent just before it exits. If you were to enter less without -X, it would send the init sequence, and if you later chose to exit without sending the deinit sequence, the terminal could be left in an inconsistent state (where arrow keys don't work correctly among other things). That's why -X is one of the few flags that can't be changed from within less.

[mcornella]

Could there be a mode where less always enters and exits the alternate screen, but upon doing so, the last printed page is also printed to the primary screen? Is something like that technically possible? This would fix the use case where a large file is scrolled through and its contents pollute the main screen, when what you really want preserved is what you last saw.

EDIT: I realize this is not technically on-topic. Let me know if I should open a new issue.

[gwsw]

Added --redraw-on-quit option in d081e3e to redraw the final screen after switching back from alternate screen. You can make Q invoke this behavior by adding this line to your .lesskey file.

Q toggle-option -!^Predraw-on-quit\nq

[mcornella]

@gwsw there's a bug when combined with -F when the input is smaller than a window, see:

There are two bugs I see here:

1. Both -F and --redraw-on-quit print the contents.
2. --redraw-on-quit prints extra ~ characters.

[gwsw]

Should be fixed in dd9a11a.

[mcornella]

Works great now, thanks!

[bew]

Added --redraw-on-quit option in d081e3e to redraw the final screen after switching back from alternate screen. You can make Q invoke this behavior by adding this line to your .lesskey file.

Q toggle-option -!^Predraw-on-quit\nq

Hello, I'm interested in this feature, when do you plan on making a release with it? (on https://greenwoodsoftware.com/)
Thank you

[gwsw]

@bew less-598 is now available for beta testing and includes this feature.

[bew]

Thank you @gwsw, I've noticed a few things(/bugs?) that prevent me from using that option just yet.
I've created #231 with my findings :)

[Chealer]

Thank you very much @jimc , @gwsw and @mcornella

Unfortunately this very useful option remains undocumented in the relevant FAQ entry.

[gwsw]

I've added a mention of --redraw-on-quit to the FAQ entry.

[Chealer]

Thank you @gwsw
But indicating the minimum version required for that option would be relevant at this time (no Red Hat Enterprise Linux release nor even Debian has it).