Re: why does git set X in LESS env var?

[Andy Koppe <andy.koppe@gmail.com>]

Thomas Guyot wrote:
> >> I actually have one major issue with it, it's that displaying anything
> >> less than a full page will fill the screen with ~ on the bottom, just
> >> like when scrolling up on a partial page  without -F.

'less' has the '-~' (or --tilde) option to suppress that.

> I mentioned it slightly above, to be clear it would mean that:
>
> 1. less starts by just writing lined down as usual, making any lines
> above scroll up and overflow into the scrollback buffer as usual
> 2.  If less draws less than a page, exits as before - the effective
> result is as if pager was cat
> 3. If less reaches a full page and still has lines to write, it turns on
> -c's behavior and further updates happen from the top of the screen,
> preventing scroll up (at least on rxvt-unicode)
>
> Now, if all other terms misbehave here, that's an issue, making this
> suggestion mostly useless. And considering the number of Windows users
> we absolutely need to test Windows Terminal, and should probably test
> MacOS's term too (whatever that is).

For what it's worth, the 'mintty' terminal used by default for Git for
Windows as well as MSYS and Cygwin has another approach to the whole
problem. Its rather flippantly named 'Flip Screen' context menu
command with Alt+F12 or Ctrl+Shift+S shortcut lets users temporarily
look at the alternate screen buffer while the main screen buffer is
active, and vice versa.

If 'less' is invoked without the -X option, it will switch to the
alternate screen, where mousewheel scrolling works by sending cursor
up/down keycodes. While in 'less', you can temporarily flip to the
main screen to look up something in the shell session there or copy
something for searching in 'less'. While looking at the main screen,
the mousewheel will scroll the scrollback buffer. Keyboard input
that's sent to 'less' will flip back to the alternate screen.

Quitting 'less' switches back to the main screen, so the 'less' output
disappears and you're back in the shell session with the command that
invoked 'less' as the last thing shown. But again, the 'Flip Screen'
command or shortcuts can be used to temporarily look at or copy from
the alternate screen, which will contain the last page displayed by
'less'. (The alternate screen does not have a scrollback buffer.)

The 'Flip Screen' feature of course also works with other
alternate-screen applications, for example editors.

Apparently the Mac terminal has such a feature as well:
https://support.apple.com/en-ie/guide/terminal/trmld1f46097/mac

(Full disclosure: I originally made mintty, from PuTTY.)

Kind regards,
Andy