Undo and redo are editing commands that step backward and forward through your recent actions. Undo reverses the latest change, such as typing, deleting or formatting, and redo reapplies a change you have undone. The usual shortcuts are Ctrl+Z and Ctrl+Y (or Ctrl+Shift+Z), with Cmd on a Mac.
Why it matters
They let people experiment without fear, because mistakes are cheap to reverse. Software typically stores actions in an undo stack. Doing a new action after undoing discards the redo stack, so the undone steps cannot be redone. The history is usually limited and cleared when you close the file, though some apps keep it.
Example
You type three sentences, delete the second and press Ctrl+Z: the deleted sentence returns. Press Ctrl+Y and it vanishes again. If after the undo you type a new word, redo is no longer available, because the app starts a new branch of history. Some editors, such as Vim, retain an undo tree.
Common mistakes
- Expecting undo to work after closing and reopening the file.
- Assuming it covers everything; file deletions, emptying a recycle bin or sent emails are often not reversible.
- Undoing too far and then typing, which erases the redo history.
Related
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यह पेज सामान्य जानकारी है, जिसे हमारी संपादकीय टीम ने लिखा है और दस्तावेज़ीकरण बदलने पर अपडेट किया जाता है। सर्वर और प्रदाता अलग-अलग होते हैं, इसलिए बदलाव पहले सुरक्षित तरीके से जाँचें। देखें: संपादकीय नीति और अस्वीकरण.