Você deve adicionar pelo menos uma coluna.
# set Key and Shift+Key
xmodmap -e "keycode 75 = Insert Insert"
# set all
xmodmap -e "keycode 75 = Insert Insert Insert Insert Insert Insert"
Each keycode is followed by the keysym it is mapped to. The above example indicates that the keycode 57 is mapped to the lowercase n, while the uppercase N is mapped to keycode 57 plus Shift.
Each keysym column in the table corresponds to a particular combination of modifier keys:
1. Key 2. Shift+Key 3. mode_switch+Key 4. mode_switch+Shift+Key 5. AltGr+Key 6. AltGr+Shift+Key
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