By default, screenshots (cmd⌘ + shift⇧ + 3) are saved on your desktop. It is possible to change this default location of screenshots, use the following command:
Mac OS X General
Hiding the files on your Mac OS X desktop
If you’re using your Mac in public, you might not want everybody to see the mess on your desktop! You can run the following command that will hide the icons from you desktop.
Disable Smooth Scrolling in Mountain Lion
In Mountain Lion 10.8 an animated smooth scrolling feature has been added to Mac OS X. Return to the pre-Smooth Scrolling functionality with this command:
Change your mouse tracking speed in Mac OS X
If the available settings in the mouse preference panel aren’t good enough for you, You can adjust the tracking speed via OS X Terminal using the following command:
Mac OS X: Disable the creation of .DS_store files
If you access a network share on Windows desktops or server, your Mac leaves .DS_store files wherever you browse. These Mac OS X system files contain data about the directory and are hidden for Mac users. You can deactivate the Writing of .DS_store Files on Networks shares, so your Windows friends will stop complaining.