For what it's worth, it seems to be a default option in Linux. xUbuntu, for me, went into Settings, Keyboard, Layout, unchecked Use System Defaults, selected a

For what it's worth, it seems to be a default option in Linux. xUbuntu, for me, went into Settings, Keyboard, Layout, unchecked Use System Defaults, selected a compose key (I picked Right Alt) Was able to do a TM by holding shift and right alt, typing TM and letting go of shift and right alt. ™ Punctuation and vowels result in accents: Û Ü Ä Ö Ô Þ Ŷ Ô ⸘ ⸘ Æ «» ¿¡ ¨ ¯--_ ⋄