AZgl1500 wrote: ↑
Fri Mar 16, 2018 10:33 pm
AltGr-Shift-0-0 does not produce any output for me.
This is as indicated dependent on the keyboard layout you use; assuming that you are using a standard US-layout keyboard hardware-wise, not having AltGr-Shift-0-0 produce anything for you likely means you are software-wise using its most plain layout, the "English (US)" one. Verify in Preferences -> Keyboard -> Layouts. As far as I am aware the "English (international AltGr dead keys)" layout is a proper superset of "English (US)" and could as such be considered a preferred choice for most any US user. If you add it in Keyboard -> Preferences -> Layouts (the +-button below the list) and look at it (the picture button) you'll note to from that point on have a lot of additional freedom of expression...
When I just now checked the layout in /usr/share/X11/xkb/symbols/us I by the way noticed the AltGr-Shift-0-0 version to be named "dead-abovering" with an explicit "degree" available from AltGr-Shift-: (AltGr-Shift-Colon). The "dead" part of that name explains the 0-0, and you should then in fact just use AltGr-Shift-Colon: 20°C = 68°F.
Putting it on Alt-o is not fully trivial (you'd manually edit the above mentioned layout file) and not something I'd advise. Alt-o is undoubtedly used natively by many programs and it moreover really pays to keep things (as) standard (as possible) with respect to keyboard layouts lest you constantly find yourself handicapped when not on your own system(s). So, advise, install "English (international AltGr dead keys)", select it (the flag symbol in the system tray) or even uninstall the previous plain "English (US)" variant so as to not have to do the latter. Print out a screenshot of the layout viewed as described above, and have some fun inputting special symbols.
[EDIT] By the way, Alt-o is a not good choice for a degree symbol in a different manner as well: it's historically not a superscript-oh but a superscript-zero...