Delete older kernels in Ubuntu

To delete older kernels in Ubuntu, an easy way is to use the Synaptic package manager:
1) Search for "linux-image", and select the old kernels for removal
2) Search for "linux-header", and select the old kernel headers for removal

Input \ instead of ¥ on Mac OS X Japanese

In order to input the backslash character "\" instead of "¥" on a Mac OS X system with Japanese keyboard settings, you should go to "System Preferences > Keyboard > Input Sources" then select the Japanese keyboard. Towards the bottom of the settings in the right pane change the setting for '"¥" key generates' to the value '\ (Backslash)'.

To make the function keys on Apple Keyboard work correctly in Ubuntu and its variants (Lubuntu, etc.), the following commands should be used to permanently set the corresponding "fnmode" property and update the configuration files:
>echo options hid_apple fnmode=2 | sudo tee -a /etc/modprobe.d/hid_apple.conf
>sudo update-initramfs -u -k all
You need to reboot after this for changes to take effect.
Reference: https://help.ubuntu.com/community/AppleKeyboard

Manually delete TimeMachine backups

Use the following command to manually delete TimeMachine backups (starting with Mac OS X Lion):
> sudo tmutil delete TimeMachine_BACKUP_NAME
Note: It is possible to delete backups of other machines than the current one.

Matlab 2013b crash at start-up

If Matlab 2013b crashes at start-up with the "java.lang.NullPointerException" error, one possible solution is to temporarily change the Mac OS X version number.

For this, change the ProductVersion value from e.g., 10.10.1 to 10.90 in the file "/System/Library/CoreServices/SystemVersion.plist".

This change can be reverted once Matlab starts (recommended, since changing the OS version seems to interfere with Safari, etc.).

Reference: http://mathworks.com/matlabcentral/newsreader/view_thread/336387