Mac hints and tips
Add menulets or menu extras to the menu bar
At the right hand side of the menu bar at the top of the screen are one or more icons and they are called menu extras by Apple, but many people call them menulets instead. You'll see a Spotlight icon, the time and/or date, possibly a battery icon and an AirPort icon. Applications and utilities that you have installed might have added more icons to the menu bar too.
These menulets can be very useful and a wide variety are available and they perform all sorts of useful functions, such as reminding you of the time, the amount of battery charge remaining, providing access to Wi-Fi networks and so on.
Many of these menulets can be added and removed from System Preferences. For example, click the Apple menu at the left hand side of the menu bar and choose System Preferences. Click Date and Time and then tick Show date and time in menu bar to add this item or clear the tick to remove it. You should explore all the other items in System Preferences and see what other menu extras are avialable.
An alternative to hunting around System Preferences for menulets is to go straight to the folder they are stored in. Open a Finder window and go to /System/Library/CoreServices/Menu Extras. You'll see a long list of items like AirPort.menu, Battery.menu, Clock.menu, and so on. These are the menulets and you can add them to the menu bar by double clicking them.
Most of the items you'll see in this folder are obvious, like TimeMachine, Bluetooth, Spaces, and so on. However, not all of them are so easy to figure out and some are not even found anywhere in the System Preferences and so there is no other way of adding them other than double clicking the .menu item in this folder.
Double click the Eject.menu menu extra to add it to the menu bar and you'll see an eject button that enables you to eject the CD or DVD that's in the drive. You might find it useful if you don't have an eject button on the keyboard. Double click CPU.menu to add it to the menu bar. You will see an icon that looks like a CPU chip with a number on it showing the number of processors (or cores) in the Mac. OK, you probably know that already, but if you click the icon you'll see a drop down menu with an interesting option on it. Select Show Processor Palette and a processor activity monitor is displayed on the desktop. It shows a live scrolling history chart that can be quite useful if you want to check on processor activity while performing some task.
Another useful menu extra is Script Menu.menu. Double click the file to add the menulet and then click the icon in the menu bar at the top of the screen. You will see a fantastic collection of useful AppleScripts organised into more than a dozen different categories. Feel free to explore the other menu extras and see what they have to offer. You will some that some are useful, but others you can live without and everyone has their personal favourites.
Removing menulets or menu extras
Having added one or more menu extras or menulets as they are sometimes called, how do you get rid of them if you decide that you don't want them after all. Most menu extras can be made visible and hidden from the appropriate item in System Preferences. For example, click the Apple logo at the left-hand side of the menu bar and choose System Preferences. Click Date and Time and then clear the tick against Show date and time in menu bar. The date and time will then be removed from the menu.
It's not easy and it's a bit tedious searching for the options among the System Preferences to remove menu extras and some items can't be found. Where is the Eject menu extra enabled or disabled? What about CPU? Fortunately, there is an easy way to remove menu extras and you don't need to scour dialog boxes and preferences. Hold down the Command key (with the Apple logo on) and then click and drag the item off the menu bar. Drop it on the desktop and it will explode in a puff of smoke. It doesn't delete the file of course, it just removes the item from the menu.
(You may find that software you have installed that has added a menu bar item can't be removed this way. You might need to open the application and go into its preferences to remove it, or even to uninstall the software.)
Rearrange menu extras/menulets
Are the menulets, or menu extras as Apple calls them, in the menu bar at the top of the screen in the most convenient order? perhpas you would like the speaker control to the left of the battery status indicator or to the right of the AirPort icon. It is possible to rearrange the order of the menu extras and it is quite an easy task. Just hold down the Command key (the one with the Apple logo on) and then click and drag the menulet to the left or right. As you do this the other items move out of the way and make room for you to drop it in its new position.
(You may find that software you have installed that has added a menu bar item can't be moved this way.)
Editing menulets/menu extras
As mentioned earlier, if you open a Finder window and go to /System/Library/CoreServices/Menu Extras you'll see a files like AirPort.menu, Battery.menu, Clock.menu, and so on. These are the menulets and while they may look like regular files, they aren't. They are folders, or packages as Apple calls them. Hold down Ctrl and click a file like Clock.menu, then choose Show Package Contents from the menu that is displayed. A new Finder window opens and displays the contents of the folder. You can browse the items in the package and see how menu extras are constructed.
Now here's an interesting thing. If you have opened Clock.menu, open the Contents folder, then Resources, then English.lproj. You will see a file called Localizable.strings. This is a text file that contains the text used in the menu extra and in the System Preferences pane. You can load this into any text editor and modify the contents. Ctrl+click it and select Open With to choose a program. If you've installed the developer tools from the OS X disc then XCode.app and Dashcode.app are suggested, but you could use another text editor.
The contents of the Localizable.strings file varies from menu extra to menu extra and they aren't all the same. Clock.menu has very descriptive comments that explain each item, so it's not too difficult to modify should you want to. You can change how the date and time format by changing or reordering the parameters in the strings. Load Battery.menu's or TimeMachine.menu's Localizable.strings into a text editor and it's different to Clock.menu. There are pairs of strings with text on the left and right of equals symbols. Change the text on the right of the equals and you replace what's on the left. You could personalise menus and messages by adding your name, or shorten them to make them more compact, or add text to make them more descriptive.
If you want to make changes though, you will need to change the ownership of the files. Ctrl+click Clock.menu, for example, and select Get Info. Down at the bottom you'll need to click the padlock and enter your password. You can then set all the priviliges to read and write. After making the changes to any of the files in the .menu package you should restore the original sharing and permission settings.
One last thing - make a backup if you are going to make changes. Copy the file to be changed to another folder and then if things go wrong you can undo the changes by copying the file back again.