I came across a rather interesting post today on the various newsgroups on the web, it was a discussion in changing the length of time in which a notification banner persists within the left hand side of the screen. These are the ones that appear when your get a new mail message, iTunes track, or a variety of other messages. With a nifty terminal trick you can change the length of time in which this message is displayed.
Changing The Length Of Time
The time in which a notification banner is present is dependant on the a notification centre preference. There is a default time built into notification centre however we can override this value. Open up Terminal located in your applications preferences folder. Copy and paste the following into Terminal. Change the value at the end to however long you want in seconds.
defaults write com.apple.notificationcenterui bannerTime 25
To apply the setting copy and paste the following into Terminal, this will restart Notification Centre.
You can quickly test the setting by playing an iTunes track and then using the next track button on your keyboard while in another app (there are many ways to test this setting, this is the easiest).
The banner time timer begins when the notification finishes its scroll down animation. Therefore, really quick times such as 0.1 seconds quickly show the notification and then you see it fly off.
Resetting The Timer
If you want to reset the time to it original you can either pick a time of about 3 to 4 seconds. The alternative route is to delete the preference.
defaults delete com.apple.notificationcenterui bannerTime; killall NotificationCenter
Again you restart notification centre.
This is a simple trick however one in which you can fine tune the setting.