My keyboard does not have separate PgUp and PgDown keys.
They are in the numpad, sharing their position with KP_9 and KP_3.
Scrolling terminals with Shift+Pg{Up,Down} was not possible either with
Numlock on or off.
Since I don't care for the keypad numbers but do care a lot for scrolling,
I have successfully remapped them in X11 to "Prior" and "Next" regardless
of Numlock state, and now Shift+{PgUp,Down} both work in Xterm.
However, I can't achieve the same in the TTY. With other keyboards that had exclusive Page keys, I could use Shift+PgUp to scroll back after cating a large file, for example.
Original keycodes
As of showkeys:
KP_3/KP_PgUp = 73
KP_9/KP_PgDown = 81
Slash = 89
Right Shift = 54
As of dumpkeys:
PgUp = 104
PgDown = 109
Slash and Right Shift were also listed because I will also swap them just
for testing.
Attempts
-
Modified
/etc/console-setup/remap.incto exactly this:keycode 73 = Prior shift keycode 73 = Scroll_Backward shift shiftl keycode 73 = Scroll_Backward shift shiftr keycode 73 = Scroll_Backward shift shiftl shiftr keycode 73 = Scroll_Backward shift ctrll keycode 73 = Scroll_Backward shift shiftl ctrll keycode 73 = Scroll_Backward shift shiftr ctrll keycode 73 = Scroll_Backward shift shiftl shiftr ctrll keycode 73 = Scroll_Backward keycode 81 = Next shift keycode 81 = Scroll_Forward shift shiftl keycode 81 = Scroll_Forward shift shiftr keycode 81 = Scroll_Forward shift shiftl shiftr keycode 81 = Scroll_Forward shift ctrll keycode 81 = Scroll_Forward shift shiftl ctrll keycode 81 = Scroll_Forward shift shiftr ctrll keycode 81 = Scroll_Forward shift shiftl shiftr ctrll keycode 81 = Scroll_Forward keycode 89 = Shift keycode 54 = slash shift keycode 54 = question altgr keycode 54 = degree shift altgr keycode 54 = questiondown -
Followed the instructions of How to change console keymap in Linux?.
dumpkeys > pageupdownThen swapped
keycode 73 keycode 104 keycode 81 keycode 109 keycode 54 keycode 89in that file and issued
loadkeys -s pageupdown.
Results
In both experiments,
-
Although the two keypad keys don't print numbers anymore and
PgUpstill
works (it scrolls inless) as desired,Shift+PgUpdoes not scroll the TTY. -
Right Shift and Slash have been correctly swapped.
Additional notes
-
Toggling Numlock does not help in any of the configurations. The Fn key
also does not have any effect in those keys. -
I have also tried mapping more
ordinary keys, namelylandp, to the Page actions, without success. -
If it helps in any way, this is the XKB map that works in the X session:
partial keypad_keys xkb_symbols "noKPNumbers" { key <KP9> { [ Prior, Prior ] }; key <KP3> { [ Next, Next ] }; };
How can I map the keypad PgUp and PgDown keys in such a way that Shift+Pg{Up,Down}
scroll the TTY buffer? Is it possible at all?
Best Answer
The reason it doesn't work is that you are trying to add form control to a formless output. There is no Buffer to scroll.
That may not seem to make sense, so let me explain. TTY is a historical artifact from when Console output was to an actual TTY or TeleTYpe device. It was a serial terminal printer, search up a LA120 from DEC for an example. You can actually still do this hooking a line printer into /dev/tty. Some server hardware also will allow you to redirect this output at the BIOS level to a serial device. It comes in darn handy if you know how to use it in the absolute worst case hardware troubleshooting scenarios.
The TTY printer would print every line just as it happened and then the paper piled up on the floor of the Operations room. What is on the screen is just what was printed within the screen buffer. there is no other retained information to scroll though.
The Console TTY is meant as a last ditch effort to retain some sort of log even when everything else shits the bed. Its where the disk full message or the seg fault that halts the system shows up to give the actual operator some clue why the system is using electricity but not being otherwise useful.