http://www.trydofor.com/2x/016.ubuntu-arrow-to-ijkl.html
https://blog.csdn.net/weixin_30664615/article/details/94995188
#把大小写变成功能键,切换大小写使用Shift-CapsLock
xmodmap -e 'keycode 66 = Mode_switch Caps_Lock'
#映射方向键
xmodmap -e 'keycode 31 = i I Up'
xmodmap -e 'keycode 44 = j J Left'
xmodmap -e 'keycode 45 = k K Down'
xmodmap -e 'keycode 46 = l L Right'
xmodmap -e 'keycode 57 = n N Home'
xmodmap -e 'keycode 58 = m M End'