[RPI3] Add screenshot software: scrot

For capture screen in Raspberry Pi 3

• open terminal
• type
  • sudo apt-get install scrot
  • 
• to use:
  • open terminal
  • type
    

    scrot	capture whole screen, image will be saved to current folder
    scrot -s	capture selected window. after hit enter, software will wait until user click any windows
    scrot -d 10	capture whole screen, with 10 second delay
    scrot -cd 10	as same as scrot -d 10, but software will display countdown number

• Manual
  • open terminal
  • type scrot -h
  • 
• make sure that you have write permission on the current folder, if not giblib error will show
  •