去除动画，立即显示Dock
defaults write com.apple.dock autohide-time-modifier -int 0;killall Dock
修改dock动画显示时间
defaults write com.apple.dock autohide-time-modifier -float 0.15;killall Dock
恢复默认设置
defaults delete com.apple.dock autohide-time-modifier;killall Dock
设置停靠多久显示dock
defaults write com.apple.dock autohide-delay -float 0; killall Dock
还原默认行为
defaults delete com.apple.dock autohide-delay; killall Dock
