In the new Reminders app, you can select several reminder lists by clicking on one, then Command-clicking on others. When you do this, the reminders will all display in one window, with a header saying, for example, 3 Lists. A smaller header will show the name of each list, with each reminder under the header for its list. If you then click the Hide Reminders button at the bottom-left of the app, you get a very neat reminders app that shows all non-completed tasks in a single list.
I found that the RSS Visualizer screensaver still works if you reinstall it from a copy of Lion.
In a Lion backup, if you still have one, go to:
/System/Library/Screen Savers/RSS Visualizer.qtz
Copy it to:
~/Library/Screen Savers/
on your Mountain Lion Mac.
[kirkmc adds: I haven't tried this, but there have been other submissions about copying screen savers from Lion to use in Mountain Lion. If you're missing your favorite system screen saver, and have a Lion backup, it's worth checking to see if it will work in Mountain Lion. Personally, I'm still using the Basic Black screensaver.]
I saw this early on in Mountain Lion, but forgot to add it as a hint (and I'm surprised no one has submitted it yet). One of the interesting features in 10.8 is the ability to rename files from the title bar. To do this, hover your cursor over a title bar, then, when the small downward-pointing arrow displays to the right of the name, click on it and choose Rename... The name in the title bar will become highlighted, and you can rename it.
(H/t OS X Daily whose post reminded me to post this hint.)
There is a gesture you can use on a trackpad to view Notification Center: swipe with two fingers from the right edge of your trackpad to the left. This works on a laptop, but with a Magic Trackpad, this really isn't easy to do, since your fingers can't slide from a surface next to the trackpad. All it generally does for me is move my trackpad to the left. (And if you happen to use the Magic Trackpad with your left hand, I'm not sure what would happen.)
So what I did is set up a hot corner on my desktop Mac, the one where I use the Magic Trackpad. To do this, go to System Preferences, then Mission Control. Click on the Hot Corners button, then choose Notification Center from one of the menus; the one for the corner you want to use. So I have it set to the top-right corner, which is logical, as that is where Notification Center lives. I just move my cursor to that corner and the Notification Center sidebar displays. To hide it, I just click elsewhere, or move the cursor to the same corner again.
Since Mountain Lion was released, I find that my Macs go to sleep when I don't want them to. I had my Energy Saver preferences set to 15 minutes, but I've noticed that when something is active, such as a download, they got to sleep after 15 minutes, rather than continue with the download. This is not only incorrect behavior, but it's very annoying. What's worse, when I changed the setting to Never, they would still go to sleep during long downloads.
The Ask Different blog pointed out that there is a new command in Mountain Lion called caffeinate. This keeps the system awake, or, as the man page says, "prevent the system from sleeping on behalf of a utility."
Run it as follows in Terminal:
caffeinate -u -t 3600
3600 in the above command is the number of seconds to keep the system awake. What's interesting is that you can effectively set your Mac to shut down at a specific time (that is, the built-in sleep mechanism will start counting when that time runs out). You can also run the command alone to keep your Mac awake until you stop it by pressing Control-C.
In Safari 6, and Mountain Lion, you can use a two-finger pinch to view and switch tabs.
Once you pinch in Safari (assuming multiple tabs are opened) you will get a view similar to that of Safari on iOS, and you can navigate among tabs using two-finger swipes to the right and left, arrow keys or a mouse or trackpad. This is an interesting way to preview all open tabs without having to load them fully.
You can either press Return, click the mouse or tap to select the frontmost tab, or pinch out to stay where you are. You can also close any tabs by clicking the close button in their headers or pressing Command-W while in this view.
[kirkmc adds: Interesting idea. I find all these gestures a bit hard to remember, but this one may actually become instinctive over time. Personally, I'll stick with Command-Shift-arrow key to cycle through tabs… Following the comments below, I've changed the category to 10.8. I had expected this to work across the board in Safari 6.]
By default Gatekeeper allows you to run apps from the Mac App Store and from verified developers. You can change this setting in the Security preference pane. If you use this setting, or the Mac App Store only setting, you can still run unsigned apps. Just Control- or right-click on an app and choose Open. Gatekeeper will display a dialog asking if you're sure you want to open the application.
[kirkmc adds: There is an extensive article on Macworld about Gatekeeper, but I felt this would be good to mention as a hint. I think most readers of this site won't use the restrictive settings, but you may work with others who do, or administer computers, and may want to launch unapproved apps on those computers from time to time.]
Mountain Lion removes RSS functionality from both Mail and Safari. To facilitate the transfer of your feeds to another RSS reader, you can collect the feed URLs by running the following script in the ~/Library/Mail/V2/RSS directory of your latest backup.
Go to: ~/Library/Mail/V2/RSS/ in your latest backup.
Run the following in Terminal: find . -name "Info.plist" -exec grep -A 1 Feed {} \; | grep string | sed 's/^[^>]*>//' | sed 's/<[^>]*>$//'
[kirkmc adds: I never used RSS with Mail or Safari so I don't see anything there.]
With Mountain Lion, you can now use the OS to encrypt disks other than the startup volume, assuming they are in GUID format. This includes USB flash drives and external Firewire/USB/ThunderBolt drives.
In the Finder, open a new window. Find your mounted (GUID) drive in the sidebar.
Control-click on the drive in the sidebar, then choose "Encrypt <drive name>." You are now prompted for your password and a hint (which is required). You will get no feedback, so wait for a few minutes; the time depends on the size of the drive.
The drive should unmount and mount again. Once this happens, your drive is encrypted.
If you choose your startup volume, this will enable FileVault II. Other drives do not enable FileVault II.
[kirkmc adds: I, for one, think this is pretty nifty. I know a lot of people who have two drives in an older laptop, where they replaced the optical drive with an SSD. Being able to encrypt the non-boot drive is quite practical, and being able to encrypt a portable drive even better.
It should be noted that there's no feedback during the encryption process. The only way you know something is happening is if the drive has an LED that shows read/write activity. And the process can take a long time; even for a 1 GB flash drive, where I tested it, it took several minutes.
Another thing to note is that an encrypted drive doesn't show up in Disk Utility. So if you need to erase that drive, you have to right-click on the drive's name and choose "Decrypt <drive name>."]
