mac os dock empty space code example
Example 1: space in dock mac
defaults write com.apple.dock persistent-apps -array-add '{"tile-type"="spacer-tile";}'
#When the terminal prompt appears again type the following command
killall Dock
Example 2: css tricks macos spaces in dock
defaults write com.apple.dock persistent-apps -array-add '{"tile-type"="spacer-tile";}'