AskDefine | Define undo

Dictionary Definition

undo

Verb

1 cancel, annul, or reverse an action or its effect; "I wish I could undo my actions"
2 deprive of certain characteristics [syn: unmake] [ant: do]
3 cause the ruin or downfall of; "A single mistake undid the President and he had to resign"
4 cause to become loose; "undo the shoelace"; "untie the knot"; "loosen the necktie" [syn: untie, loosen]
5 remove the outer cover or wrapping of; "Let's unwrap the gifts!"; "undo the parcel" [syn: unwrap] [ant: wrap] [also: undone, undid]

User Contributed Dictionary

English

Pronunciation

  • /ʌnˈduː/, /Vn"du:/
  • Rhymes with: -uː

Homophones

Verb

  1. To reverse the effects of an action.
    Fortunately, we can undo most of the damage to the system.
  2. To unfasten.
    Could you undo my buckle for me?

Synonyms

sense 1

Translations

to reverse
to unfasten

Extensive Definition

For Wikipedia's "undo" function, see Help:Reverting#Undo.
Undo is a command in most creative programs. It erases the last change done to the document reverting it to an older state. In some more advanced programs such as graphic processing, undo will negate the last command done to the file being edited. Undo is used in many programs and is a helpful feature.
The opposite of undo is redo. The redo command reverses the undo or advances the buffer to a more current state.
In most Windows applications, the Undo command is activated by pressing Ctrl-Z. In most Macintosh applications, the Undo command is activated by pressing Command-Z. The common command for Redo on Microsoft Windows systems is Ctrl-Y or Ctrl-Shift-Z. The common command for Redo on Apple Macintosh systems is Command-Shift-Z.

Undo models

Undo models can be categorized according to two criteria: linear vs non-linear, and single-user vs multi-user. Linear undo requires the user to revert the latest action before undoing earlier ones. With non-linear undo, the action to be reverted can be freely picked from the action history list.
Non-linear undo can be further subcategorized into direct selective undo vs. script interpretation undo.
When multiple users can edit the same document simultaneously, a multi-user undo is needed. Global multi-user undo reverts the latest action made to the document, regardless of who performed the edit. Local multi-user undo only reverts actions done by the local user. Local multi-user undo usually requires a non-linear undo implementation.
The number of previous actions that can be undone varies by program. For example, the stack size ranges from twenty in Photoshop to three edits in MS Paint. Simplistic, single-edit undo features sometimes do away with "redo" by treating the undo command itself as an action that can be undone. This is known as the flip undo model, because the user can flip between two program states using the undo command.

Undo implementation

The Command pattern is a software design pattern which can be used to implement Multi-level Undo. The Memento pattern is useful for capturing the state of the program before user actions. This can be used for state reversal needed in some undo implementations.

External links

undo in German: Undo

Synonyms, Antonyms and Related Words

KO, abate, abolish, abrogate, annihilate, annul, answer, atomize, bare, beat, beat all hollow, beat hollow, best, bottom, break to pieces, bring down, bring to naught, bring to nothing, buffer, cancel, cancel out, cast off, clear, clear up, cleave, come to nothing, cook, counterbalance, crack, crush, dash, debauch, debug, decimate, decipher, decode, defeat, demolish, demoralize, deobstruct, destroy, detach, disassemble, disclose, disengage, disentangle, dish, disintegrate, dismantle, divine, do, do for, do in, doff, dope, dope out, douse, drop, drub, explain, expose, fathom, figure out, find out, find the answer, find the solution, fix, fragment, free, frustrate, get, get right, guess, guess right, have, have it, hide, hit it, hors de combat, interpret, invalidate, knock down, knock out, lambaste, lather, liberate, lick, loose, loosen, make mincemeat of, make out, manifest, negate, negativate, negative, neutralize, nullify, offset, ope, open, open the lock, outclass, outdo, outfight, outfox, outgeneral, outmaneuver, outpoint, outreach, outrun, outsail, outshine, outsmart, overcome, overreach, patefy, pick to pieces, plumb, prostrate, psych, psych out, pull in pieces, pull to pieces, pulverize, put, put off, puzzle out, quash, ravel, ravel out, raze, reduce to rubble, release, remove, rend, repeal, rescind, resolve, reveal, reverse, revoke, riddle, ruin, scuttle, settle, shake, shatter, shoot down, sink, skin, skin alive, slip out of, smash, solve, sort out, split, step out of, stultify, sunder, take apart, take off, tear apart, tear to pieces, tear to shreds, tear to tatters, thrash, throw off, thwart, torpedo, total, trim, triumph over, trounce, unbar, unbind, unblock, unbolt, unbrace, unbuckle, unbuild, unbutton, uncase, unchain, unclasp, unclench, unclog, unclutch, uncork, uncover, uncurtain, undrape, unfasten, unfetter, unfold, unfoul, unglue, unhook, unlace, unlatch, unleash, unlock, unloose, unloosen, unmake, unman, unnerve, unplug, unravel, unriddle, unroll, unscramble, unseal, unsheathe, unshut, unsnap, unstick, unstop, unstrap, unstring, untangle, untie, untwist, unveil, unweave, unwrap, unzip, upset, vitiate, void, weigh anchor, whip, work, work out, worst, wrack, wrack up, wreck
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