While recently playing around with my keyboard and looking at ways to enter special characters I discovered that the Alt key (that's the one on the left, i.e. *not* the AltGr key) doesn't act as a modifier like the AltGr key but, in some cases, acts as a multiplier for the next character.
I.e. if I enter Alt+<digit> the prompt changes to (arg: <digit>) and entering further Alt+<digit> keys adds to the value after arg:. Then on entering the next character it is repeated arg times. This is (for me anyway) a totally useless facility, I'd much rather the Alt key acts as a shift key (like the AltGr key) and gives special characters.
I have some documentation that gives the standard/default characters generated by Alt and AltGr as follows (intermediate mail systems willing):-
Unshifted Shifted Unshifted Shifted Key Alt AltGr Alt AltGr Key Alt AltGr Alt AltGr ` à | ¬ 1 ± ¹ ¡ ¡ A á æ Á Æ 2 ² ² ¢ S ó ß Ó § 3 ³ ³ £ £ D ä ð Ä Ð 4 ´ ¤ ¼ F æ Æ ª 5 µ ½ ¥ G ç Ç 6 ¶ ¾ Þ H è È 7 · ¦ J ê Ê 8 ¸ ª K ë Ë 9 ¹ ¨ ± L ì Ì 0 ° © ° ; » º - ß ¿ ' § À = ½ « # £ þ
Q ñ Ñ \ Ü ü ¦ W ÷ × Z ú « Ú < E å Å X ø » Ø > R ò ¶ Ò ® C ã ¢ Ã © T ô Ô V ö Ö Y ù Ù ¥ B â Â U õ Õ N î n Î N I é É M í µ Í º O ï ø Ï Ø , ¬ ¼ × P ð þ Ð Þ . ® · ¾ ÷ [ Û û / ¯ ¿ ] Ý ý
In all my terminal windows the above AltGr combinations work but none of the Alt ones do, I'd like the Alt ones as well. I could then type things like ¢ (cents) and ® (registered) without too much hassle. (The above ways of typing accented characters aren't so much use as they're not easy to remember and I use a Compose key to do them)