I routinely hide the Dock on my Macbook Air, since it takes up a significant portion of my screen. While I use Alfred most of the time to launch apps and such, I still like to use the Dock; call it a hold over from the last ten years or so.
Sometimes, though, when I move the mouse cursor over to the side of the screen I keep the Dock on (the left, if you’re curious), it pops up even when I don’t want it to.
Then I found this Terminal command which lets me set the time delay between when my cursor hits the edge of my screen and when the Dock actually appears. Now I have the delay period set to a larger number, making it much slower to respond and unhide.
Launch Terminal from the Utilities folder, which is inside the Applications folder. Once launched, type or paste the following command in:
defaults write com.apple.Dock autohide-delay -float 1
to restart the Dock process to see the changes.
That gives you a full one second of delay. If you want a longer delay, make the number bigger, like 1.5 or 2. If you want a shorter delay, you can type in 0.1 or 0.5.
Now you have more control over how fast–or slow–the Dock will unhide when you hover your cursor over the edge of the screen. For me, that means the Dock stays put unless I hover over it for a full two seconds; perfect for making sure of my intentions.
If you want to put the Dock back to default, simply type or paste in the following:
defaults delete com.apple.Dock autohide-delay
Then type in
killall Dock to restart it all, again.
Via: Mac OS X Tips