
desc: get manual for specific command

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eg: man cd

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system shortcut list:

tab                 :  get prompt for current typing
ctrl + backspace    :  delete previous word in command line
ctrl + delete       :  delete next word in command line
shift + backspace   :  clean command line
ctrl + left arror   :  move caret to previous word in command line
ctrl + right arror  :  move caret to next word in command line
ctrl + c            :  copy selected text from command line
ctrl + v            :  paste text to command line
ctrl + d            :  show all parameters of current string interface
ctrl + s            :  save
ctrl + n            :  switch 3dAxes visibility
up arrow            :  previous command
down arrow          :  next command
esc                 :  hide cmd ui or leave system
ctrl + e            :  show cmd ui
ctrl + left mouse button + drag   :  rotate camera
ctrl + mid mouse button scroll    :  zoom
ctrl + right mouse button + drag  :  zoom
ctrl + p            :  colour select window
ctrl + b            :  switch ui background visibility
ctrl + =            :  turn up alpha of ui background
ctrl + -            :  turn down alpha of ui background
