Alternatively referred to as Control D and C-d, Ctrl+D is a shortcut key that varies depending on the program. For example, in most Internet browsers, Ctrl+D is used to add the current site to a bookmark or favorite.
How to use the Ctrl+D shortcut key
On Apple computer keyboards, the Ctrl key is labeled as "control."
Ctrl+D in an Internet browser
Ctrl+D in Excel and Google Sheets
In Microsoft Excel and Google Sheets, pressing Ctrl+D fills the cell beneath with the contents of the selected cell in a column. To fill more than one cell, select the source cell and press Ctrl+Shift+Down to select all cells. Then press Ctrl+D to fill them with the contents of the original cell.
Google Sheets and Microsoft Excel both share this shortcut but have slightly different steps. In Microsoft Excel, pressing Ctrl+D in a cell with text in the cell directly above it will fill the cell. However, in Google Sheets you must highlight the first cell and all cells below it to fill and then press Ctrl+D. Highlighting the cells in Microsoft Excel also fills all highlighted cells.
Using the Ctrl+R shortcut will fill a row instead of a column.
Ctrl+D in Microsoft PowerPoint
In Microsoft PowerPoint, the Ctrl+D shortcut key inserts a duplicate of the selected slide. Select the desired slide in the thumbnail pane on the left side of the PowerPoint program window, then press the Ctrl+D shortcut key.
Ctrl+D in Microsoft Word
Ctrl+D in the Linux shell
In the Linux command-line shell, pressing Ctrl+D logs out of the interface. If you used the sudo command to execute commands as another user, pressing Ctrl+D exits out of that other user and puts you back as the user you originally logged into.
Related keyboard shortcuts
Below are links to related keyboard key and keyboard shortcut pages.