CtrlD

CtrlD is a keyboard shortcut formed by pressing the Control key together with the letter D. Its function varies across software environments, so the exact action depends on the application in use.

In Unix-like terminals and shell environments, Ctrl+D sends an end-of-file (EOF) signal to the active program. If the input buffer is empty at a shell prompt, this typically logs the user out or closes the session; when a program is reading input, it ends the input stream.

In office applications, Ctrl+D has different uses by program. For example, in Microsoft Word it opens the Font dialog to change font attributes, while in Microsoft Excel it performs Fill Down, copying the contents of the active cell to cells below in a selected range.

In web browsers, Ctrl+D bookmarks the current page in most browsers, providing a quick way to save pages for later reference. In some contexts or browsers, the shortcut may perform a slightly different bookmarking action or be configurable by the user.

In graphics editors, Ctrl+D can have actions such as deselecting a selection (notably in some programs like Photoshop). In text editors and integrated development environments (IDEs), Ctrl+D is commonly mapped to editing conveniences such as duplicating the current line or selection, or adding the next occurrence for multi-cursor editing. The exact mapping varies by editor and platform.

Because Ctrl+D is not standardized across software, users should consult the specific application's help or keyboard shortcuts reference to confirm its action in that context. On macOS, the equivalent often uses the Command key (for example, Command+D in browsers to bookmark).