Undo is an interactive technique implemented in many computer programs. Revert back to the last change made to the document or reverts to the old state. For more advanced programs, such as graphics processing, undoing will invalidate the last command executed on the file being edited. It’s can easily be undone., so users can easily undo, so they can explore and work without fear of mistakes.

The expectations for undo are easy to understand. It has predictable functionality and is to include all undo commands. In general, you can undo all actions performed by the user until you undo them. However, some actions are not saved in the undo list and cannot be undone. For example, saving a file is undoable, but is queued in a list to indicate that it has been performed. Another action that is not normally saved and undoable is scrolling or selecting.

Common components of the undo feature are commands executed for the user, a history buffer to store completed actions, an undo/redo manager to control the history buffer, and a user to interact with the user. Interface.

In most Microsoft Windows applications, the keyboard shortcut for the Undo command is Ctrl + Z or Alt + Backspace, and the shortcut for redo is Ctrl + Y or Ctrl + Shift + Z.

In most Apple Macintosh applications, the shortcut for the Undo command is Command-Z, and the shortcut for Redo is Command-Shift-Z or Command-Y.

The ability to undo computer operation actions was independently invented multiple times, depending on how people used the computer.

The file search and editing system developed at Brown University in 1968 is reported to be the first computer-based system with an “undo” function.

Warren Teitelman developed Programmer’s Assistant as part of the BBN-LISP with undo function by 1971.

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