(Basic Undo): Renamed from Undo. Most of text moved to new Undo node.

man/basic.texi

@@ -21,7 +21,7 @@ use the tutorial, run Emacs and type @kbd{Control-h t}
 * Moving Point::        How to move the cursor to the place where you want to
 			  change something.
 * Erasing::	        Deleting and killing text.
-* Undo::	        Undoing recent changes in the text.
+* Basic Undo::	        Undoing recent changes in the text.
 * Files: Basic Files.   Visiting, creating, and saving files.
 * Help: Basic Help.     Asking what a character does.
 * Blank Lines::	        Commands to make or delete blank lines.
@@ -312,73 +312,33 @@ line, it kills all the text up to the end of the line.  If you type
 
   @xref{Killing}, for more flexible ways of killing text.
 
-@node Undo
+@node Basic Undo
 @section Undoing Changes
-@cindex undo
-@cindex changes, undoing
 
-  You can undo all the recent changes in the buffer text, up to a
-certain point.  Each buffer records changes individually, and the undo
-command always applies to the current buffer.  Usually each editing
-command makes a separate entry in the undo records, but some commands
-such as @code{query-replace} make many entries, and very simple commands
-such as self-inserting characters are often grouped to make undoing less
-tedious.
+  Emacs records a list of changes made in the buffer text, so you can
+you can undo all the recent changes, as far as the records go.
+Usually each editing command makes a separate entry in the undo
+records, but sometimes an entry covers just part of a command, and
+very simple commands may be grouped.
 
 @table @kbd
 @item C-x u
-Undo one batch of changes---usually, one command worth (@code{undo}).
+Undo one entry of the undo records---usually, one command worth
+(@code{undo}).
 @item C-_
 @itemx C-/
 The same.
 @end table
 
-@kindex C-x u
-@kindex C-_
-@kindex C-/
-@findex undo
   The command @kbd{C-x u} (or @kbd{C-_} or @kbd{C-/}) is how you undo.
 The first time you give this command, it undoes the last change.
 Point moves back to where it was before the command that made the
 change.
 
-  Consecutive repetitions of @kbd{C-_} or @kbd{C-x u} undo earlier and
-earlier changes, back to the limit of the undo information available.
-If all recorded changes have already been undone, the undo command
-displays an error message and does nothing.
-
-@findex undo-only
-  Any command other than an undo command breaks the sequence of undo
-commands.  Starting from that moment, the previous undo commands become
-ordinary changes that you can undo.  Thus, to redo changes you have
-undone, type @kbd{C-f} or any other command that will harmlessly break
-the sequence of undoing, then type more undo commands.  On the other
-hand, if you want to ignore previous undo commands, use @kbd{M-x
-undo-only}.  This is like @code{undo}, but will not redo changes
-you have just undone.
-
-  If you notice that a buffer has been modified accidentally, the
-easiest way to recover is to type @kbd{C-_} repeatedly until the stars
-disappear from the front of the mode line.  At this time, all the
-modifications you made have been canceled.  Whenever an undo command
-makes the stars disappear from the mode line, it means that the buffer
-contents are the same as they were when the file was last read in or
-saved.
-
-  If you do not remember whether you changed the buffer deliberately,
-type @kbd{C-_} once.  When you see the last change you made undone, you
-will see whether it was an intentional change.  If it was an accident,
-leave it undone.  If it was deliberate, redo the change as described
-above.
-
-  Normal undo applies to the buffer as a whole.  You can also
-selectively undo changes in any part of the buffer (@pxref{Selective
-Undo}).
-
-  Some specialized buffers do not record undo information.  Buffers
-whose names start with spaces never do; these buffers are used
-internally by Emacs and its extensions to hold text that users don't
-normally look at or edit.
+  Consecutive repetitions of @kbd{C-x u} (or its aliases) undo earlier
+and earlier changes, back to the limit of the undo information
+available.  If all recorded changes have already been undone, the undo
+command displays an error message and does nothing.
 
   The undo command applies only to changes in the buffer; you can't
 use it to undo mere cursor motion.  However, some cursor motion
@@ -386,42 +346,6 @@ commands set the mark, so if you use these commands from time to time,
 you can move back to the neighborhoods you have moved through by
 popping the mark ring (@pxref{Mark Ring}).
 
-@vindex undo-limit
-@vindex undo-strong-limit
-@vindex undo-outer-limit
-@cindex undo limit
-  When the undo information for a buffer becomes too large, Emacs
-discards the oldest undo information from time to time (during garbage
-collection).  You can specify how much undo information to keep by
-setting three variables: @code{undo-limit}, @code{undo-strong-limit},
-and @code{undo-outer-limit}.  Their values are expressed in units of
-bytes of space.
-
-  The variable @code{undo-limit} sets a soft limit: Emacs keeps undo
-data for enough commands to reach this size, and perhaps exceed it,
-but does not keep data for any earlier commands beyond that.  Its
-default value is 20000.  The variable @code{undo-strong-limit} sets a
-stricter limit: a previous command (not the most recent one) which
-pushes the size past this amount is itself forgotten.  The default
-value of @code{undo-strong-limit} is 30000.
-
-  Regardless of the values of those variables, the most recent change
-is never discarded unless it gets bigger than @code{undo-outer-limit}
-(normally 3,000,000).  At that point, Emacs discards the undo data and
-warns you about it.  This is the only situation in which you cannot
-undo the last command.  If this happens, you can increase the value of
-@code{undo-outer-limit} to make it even less likely to happen in the
-future.  But if you didn't expect the command to create such large
-undo data, then it is probably a bug and you should report it.
-@xref{Bugs,, Reporting Bugs}.
-
-  The reason the @code{undo} command has three key bindings, @kbd{C-x
-u}, @kbd{C-_} and @kbd{C-/}, is that it is worthy of a
-single-character key, but @kbd{C-x u} is more straightforward for
-beginners to type.  Meanwhile, @kbd{C--} on a text-only terminal is
-really @kbd{C-_}, which makes it a natural and easily typed binding
-for undoing.
-
 @node Basic Files
 @section Files