I would like to set multiple keyboard shortcuts doing the same thing. My particular example is Volume Up/Down, I would like to retain the standard settings I have (Sound/VolumeUp - XF86AudioRaiseVolume, my laptop dedicated button) and I would like to add a second set (Tux+Up). How can I do that? Thanks a lot.
In Gnome just go to Settings->Keyboard and click the Shortcuts tab.
You can redefine your 'Sound and Media' shortcuts and you can define custom shortcuts to execute special commands. As long you not use the same shortcut more than once, but in this case you'll get a warning message.
I know this is a late answer, but I was having a similar issue and found a solution that should also work for your case (or anyone else brought here by Google as I was).
To map additional keyboard shortcuts to common media controls, you can install playerctl, and map additional shortcuts to use it.
OSTechNix has an article I found very useful in explaining how to use playerctl. In my case, I wanted another shortcut for Play/Pause to use on my work keyboard, without interfering with the media controllers on my home keyboard. So I mapped the additional shortcut to
Check out playerctl's man page for information on it's volume functionality. I'd post more on that, but it doesn't seem to be compatible with my configuration.