spectacle

Basic window actions
To move a window to the center of the screen use the ⌥⌘C keyboard shortcut. Centered windows will not have their size altered. Maximize a window using the ⌥⌘F shortcut.
Windows can be moved to a number of predefined regions of the screen:
Move to the left half — ⌥⌘←
Move to the right half — ⌥⌘→
Move to the top half — ⌥⌘↑
Move to the bottom half — ⌥⌘↓
Move to the upper left — ⌃⌘←
Move to the lower left — ⌃⇧⌘←
Move to the upper right — ⌃⌘→
Move to the lower right — ⌃⇧⌘→