Ctrl+Z is a keyboard shortcut used to undo the previous action in most programs that support it. It is alternatively called Control+Z and C-z, ^z. To use this keyboard shortcut, press and hold either Ctrl key, and while continuing to hold, press Z. Most programs that support the Ctrl+Z keyboard shortcut allow you to use it multiple times. For example, you could press and hold Ctrl, and then press Z three times to undo the last three changes (if they exist) . In addition to undoing actions, some programs also allow you to redo actions using the Ctrl+Y keyboard shortcut.

It is important to note that Ctrl+Z has different functions in different contexts. For example, in Linux-based operating systems such as Ubuntu, Ctrl+Z is used to suspend a process, which means that the program or command you are running will be temporarily halted and put in the background, taking up no resources. In Microsoft Excel and other spreadsheet programs, pressing Ctrl+Z will undo any change made in a spreadsheet. In Microsoft PowerPoint, Ctrl+Z will undo any edit made to a presentation. In Microsoft Word and other word processors, pressing Ctrl+Z will undo any change made in a document. When using the MS-DOS copy con command, pressing Ctrl+Z finalizes the creation of a file and then saves it. In a command line interface, such as Linux and Unix, Ctrl+Z is used to send a TSTP (temporary stop) signal to request it to stop temporarily.