Draws a thin border around the outside of the selection and leaves the lines between the cells inside alone. Ctrl+Shift+- (Cmd+Option+- on a Mac) removes every border from the selection again.
More Format shortcuts
- Apply the Currency formatCtrl+Shift+4
- Apply the Date formatCtrl+Shift+3
- Open Format CellsCtrl+1
- Group rows or columnsAlt+Shift+Right
- Hide the selected columnsCtrl+0
- Hide the selected rowsCtrl+9
- Apply the Number formatCtrl+Shift+1
- Apply the percent formatCtrl+Shift+5
- Apply the Scientific formatCtrl+Shift+6
- Apply strikethroughCtrl+5
- Apply the Time formatCtrl+Shift+2
- Ungroup rows or columnsAlt+Shift+Left
- Unhide rowsCtrl+Shift+9