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

From: Dragan Simic <dsimic@manjaro.org>
Date: Nov 3, 2023, 18:38 UTC
Message-ID: <db923ad4f3fba79e2a2e279f6d5aff16@manjaro.org>
In-Reply-To: <CAHWeT-aftfawZ9DhqC1NkQrJAuArJZC65ZDr4FyPwEc7aXGVuA@mail.gmail.com>

On 2023-11-03 16:28, Andy Koppe wrote:

Show 6 quoted lines

> 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.

Good to know, thanks. However, with the "-F" option in place, the situation in which less than a full page is displayed within less(1) shouldn't be encountered.

Show 6 quoted lines

> 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.

This is a rather neat feature. Though, I wonder how many users are actually aware of this feature, and how frequently is it used. I wasn't aware of it, and I used Git CLI on Windows for some time.

Show 7 quoted lines

> 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.

To me, this is another confirmation that (ab)using the "-X" option is something that we need to get rid of, as I already described earlier in this email thread.

Show 12 quoted lines

> 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

Maybe there is some data available about how frequently this neat feature is used? It would be really good to know how much is it actually used.

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 (Full disclosure: I originally made mintty, from PuTTY.)

Thanks for your work!