moar supports two mouse modes (using the --mousemode parameter):

• scroll makes scrolling work, but will require some gymnastics for copying text with your mouse, see below.
• mark makes copying text work, but on some terminals this will break scrolling.
• auto uses mark on terminals where we know it won't break scrolling, and scroll on all others. The white list lives in the mouseTrackingRecommended() function in screen.go.

The reason is that if moar requests mouse events from the terminal, that will make the terminal not accept mark / copy any more.

If moar doesn't request mouse events, then some terminals will send arrow keys instead when you scroll your mouse wheel, making scrolling still work. Some other terminals will send nothing, making scrolling not work.

less --mouse has the same problems.

• Alacritty: Use use shift mouse selection to make it work. Cred to @chrisgrieser for this tip.
• Foot: Use use shift mouse selection to make it work. Cred to @postsolar for this tip.
• Hyper on macOS: Set macOptionSelectionMode: 'force' in your config file, then hold the Option Key ⌥ while marking
• iTerm: Preferences / Profiles / Default / Terminal / uncheck "Report mouse clicks & drags"
• macOS Terminal on a laptop: Hold down the fn key while marking with the mouse
• kitty on macOS: Holding shift or fn while marking. Cred to @PrayagS for this tip.
• Konsole Use use shift mouse selection. Cred to @cig0 for this tip.
• Terminator: Use use shift mouse selection to make it work. Cred to @felix-seifert for this tip.
• Tilix: Use use shift mouse selection. Cred to @Macr0Nerd for this tip.
• Warp: Preferences / Settings / Features / Terminal / uncheck "Enable Mouse Reporting"
• Windows: Use Shift to make a selection. If you click the wrong initial spot, you can clear the selection with Esc. Just be careful, if you hit Esc without a selection, the pager will exit. Cred to @89z for this one.

Recorded using iTerm's Automatically log session input to files feature.

less is version 487 that comes with macOS 11.3 Big Sur.

All linebreaks are mine, added for readability. The ^Ms are not.

less /etc/passwd
^G<ESC>[30m<ESC>(B<ESC>[m^M
<ESC>[?1049h
<ESC>[?1h
<ESC>=^M
##

moar /etc/passwd /Users/johan/src/moar
^G<ESC>[30m<ESC>(B<ESC>[m^M
<ESC>[?1049h
<ESC>[?1006;1000h
<ESC>[?25l
<ESC>[1;1H
<ESC>[m<ESC>[2m  1 <ESC>[22m##

The line starting with ^G is probably from from fish since it's the same for both less and moar.

<ESC>[?1049h switches to the Alternate Screen Buffer, search here for 1 0 4 9 for info.

Then less does [?1h, which apparently is DECCKM Cursor Keys Mode, send ESC O A for cursor up, followed by =, meaning DECKPAM - Set keypad to applications mode (ESCape instead of digits).

NOTE that this means that less version 487 that comes with macOS 11.3 Big Sur doesn't even try to enable any mouse reporting, but relies on the terminal to convert scroll wheel events into arrow keypresses.

Same as less up until the Alternate Screen Buffer is enabled.

<ESC>[?1006;1000h enables SGR Mouse Mode and the X11 xterm mouse protocol (search for 1 0 0 0).

<ESC>[?25l hides the cursor. NOTE Maybe we don't need this? It might be implicit when we enable the Alternate Screen Buffer.

<ESC>[1;1H moves the cursor to the top left corner.

Then it's the first line with its line number in faint type.