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<h2>UBU</h2>undo the <a href="COMMAND.html">command</a>s back up to (not including) a <a href="COMMAND.html">command</a> descriptor
<pre>Major Section: <a href="HISTORY.html">HISTORY</a>
</pre><p>
<pre>
Examples:
:ubu :x-3 ; undo the last three commands (same as :ubt :x-2)
:ubu (:x -3) ; same as above
:ubu fn ; undo back up to, but not including the introduction of fn
; (so fn will continue to be defined)
:ubu 5 ; undo back up to, but not including, the fifth command
; executed (leaving the first five commands in place)
</pre>
See <a href="COMMAND-DESCRIPTOR.html">command-descriptor</a>.
<p>
<code>Ubu</code> takes one argument, a <a href="COMMAND.html">command</a> descriptor, and undoes the
<a href="COMMAND.html">command</a>s from <code>:</code><code><a href="MAX.html">max</a></code> (aka <code>:x</code>) up to, but not including, the
indicated command. See <a href="COMMAND-DESCRIPTOR.html">command-descriptor</a>.<p>
<code>Ubu</code> can cause errors or queries. To avoid these, see <a href="UBU_bang_.html">ubu!</a>.<p>
Also see <a href="UBT.html">ubt</a>, which is similar but also undoes the indicated command. As
for <code>:</code><code><a href="UBT.html">ubt</a></code>, <code>:</code><code><a href="OOPS.html">oops</a></code> will undo the undo (see <a href="OOPS.html">oops</a>) and
<code><a href="UBU.html">ubu</a></code> will not undo into ``prehistory''.<p>
See <a href="U.html">u</a> for how to undo just the latest command, and see <a href="UBT.html">ubt</a> and see <a href="UBT_bang_.html">ubt!</a> for
how to undo back through (that is, including) the current command.
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