master 7fec0a4: Document easy ways of typing undo key on TTY frames

[Eli Zaretskii]

branch: master
commit 7fec0a444eb6c9e871326ab5b5d5eefb14e513fd
Author: Richard Stallman <rms@gnu.org>
Commit: Eli Zaretskii <eliz@gnu.org>

    Document easy ways of typing undo key on TTY frames
    
    * doc/emacs/basic.texi (Basic Undo): Document the easiest way to
    type the undo key.
    
    * etc/tutorials/TUTORIAL: Describe typing C-_ without the Shift
    key.
---
 doc/emacs/basic.texi   | 8 ++++++++
 etc/tutorials/TUTORIAL | 1 +
 2 files changed, 9 insertions(+)

diff --git a/doc/emacs/basic.texi b/doc/emacs/basic.texi
index 0b685fa..444b246 100644
--- a/doc/emacs/basic.texi
+++ b/doc/emacs/basic.texi
@@ -461,6 +461,14 @@ Normally, this command undoes the last change, moving 
point back to
 where it was before the change.  The undo command applies only to
 changes in the buffer; you can't use it to undo cursor motion.
 
+  On a graphics terminal (including text-mode frames displayed by a
+terminal emulator, such as @command{xterm}), the easiest way to invoke
+@code{undo} is with @kbd{C-/}; that doesn't need the Shift key.  On a
+text terminal, @kbd{C-/} does not exist, but in many cases you can type
+@kbd{C-_} without the Shift key (in effect pressing @kbd{C--}) and it
+will work anyway, at least with keyboards that produce the US ASCII
+character set.
+
   Although each editing command usually makes a separate entry in the
 undo records, very simple commands may be grouped together.
 Sometimes, an entry may cover just part of a complex command.
diff --git a/etc/tutorials/TUTORIAL b/etc/tutorials/TUTORIAL
index 227c13f..319ba52 100644
--- a/etc/tutorials/TUTORIAL
+++ b/etc/tutorials/TUTORIAL
@@ -473,6 +473,7 @@ to undo insertion of text.)
 >> Kill this line with C-k, then type C-/ and it should reappear.
 
 C-_ is an alternative undo command; it works exactly the same as C-/.
+On some text terminals, you can omit the shift key when you type C-_.
 On some text terminals, typing C-/ actually sends C-_ to Emacs.
 Alternatively, C-x u also works exactly like C-/, but is a little less
 convenient to type.