Arcana
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   * Q3.2  How do i get Shift-Tab to go backwards on a text terminal or
     XTerm?

     aka: I hate the new text widgets, I can't go through the links
     with n and b      I can go forward using TAB but how do i go
     backward on a terminal?

     Thanks to Greg Stark <gsstark@mit.edu> for this incredibly thorough
     answer.  I have verified that this works on my Linux laptop.

     Not all terminals can distinguish between a shifted tab and an
     unshifted tab at all. Tab is indicated on a text terminal by a
     control-i. There is no such thing as capital control characters,
     so if the terminal is going to indicate a shift-tab somehow it has
     to be completely differently. The most appropriate thing to use is
     probably "backtab" which on old text terminals was sometimes a
     separate key and Emacs is already set up to recognize
     automatically if it exists.

     Making "backtab" work involves several steps. First you have to
     make sure your console generates some character sequence to
     indicate the key you want to generate a "backtab". Then you have
     to configure termcap or terminfo to recognize that key sequence.
     Then you may have to make your programs do useful things when they
     get a "backtab", Emacs for example will recognize it automatically
     but except for the Widget and W3 commands nothing is ever bound it
     it.

     Step 1 On An XTerm: XTerm obeys standard X Toolkit translations
     which you can use to specify what character sequence Shift-Tab
     generates. The following X Resources will cause Shift-Tab and
     Meta-Shift-Tab to generate reasonable character sequences. You can
     either put this in your .Xresources or .Xdefaults file, or you can
     put it in /usr/lib/X11/app-defaults/XTerm to make it a site-wide
     default. (On Debian systems you should put it in
     /etc/X11/Xresources, not the app-defaults files):

          XTerm*VT100.translations: #override \
             ~Meta Shift<Key>Tab: string(\033[Z) \n\
              Meta Shift<Key>Tab: string(\033\033[Z) \n

     I recommend these sequences, they are based on what seems to be a
     more or less standard sequence ^[[Z for backtab.

     Step 1 On Rxvt: By default Rxvt sends ^[[Z for Shift-Tab.
     However, if Shift-Tab generates another keysym, like for example
     in XFree86 3.2 where it's bound to ISO_Left_Tab then Rxvt will
     just ignore it. You would need to defeat this feature to make rxvt
     work again by doing something like:

          xmodmap -e 'keysym Tab = Tab'

     or adding that command to some global X configuration file (On
     Debian systems adding "Keysym Tab = Tab" to /etc/X11/Xmodmap or
     ~/.Xmodmap is sufficient)

     Step 1 On A Linux Virtual Console: on a Linux virtual console you
     can configure what character sequences are generated by which keys
     using the loadkeys command. Many systems are set up to run
     loadkeys automatically on startup with some keymap file. On Debian
     systems this is true, the keymap file is specified in
     /etc/kbd/config and usually lives in the /usr/lib/kbd/keytables
     directory. You want to put something like the following in your
     keytable file:

          keycode  15 = Tab   F91
          	alt     keycode  15 = Meta_Tab
          	shift   alt     keycode  15 = F92

     where keycode 15 is Tab on my keyboard (and probably any
     keyboard). This defines Tab and Alt-Tab normally, and also defines
     Shift-Tab to be F91 and Shift-Alt-Tab to be F92.

     Then put something like this:

          # backtab and M-backtab
          string F91 = "\033[Z"
          string F92 = "\033\033[Z"

     later in the file. This defines what character sequence F91
     (Shift-Tab) and F92 (Alt-Shift-Tab) should generate. I recommend
     these sequences, they are based on what seems to be a more or less
     standard sequence ^[[Z for backtab.

     Step 2 On A Termcap System:

     The termcap capability is kB, i'm not familiar with termcap tools,
     i think you just need to add it to the /etc/termcap file for the
     terminal you're concerned with as kB=\E[Z.

     Step 2 On A Terminfo System:

     The terminfo capability is kcbt (the long name is key_btab). You
     want to run infocmp to generate an edittable copy of the terminal
     info. Add the capability, then use tic to compile that
     information. Something like this:

     infocmp $TERM > info emacs info & # add kcbt=\E[Z, to the file tic
     info

     If you do this as root it should add the new definition to the
     system wide terminfo database. If you do it as a normal user it
     should create a ~/.terminfo database with a local terminfo info
     definition for that terminal.

     Step 3 On Emacs:

     The standard terminal initialization should recognize the backtab
     capability automatically. To test it try C-h c Shift-Tab and see
     what it calls the key.  To bind commands to it just use [backtab]
     in local-set-key or global-set-key as in:

          (local-set-key [backtab] 'hippie-expand)
          or
          (global-set-key [backtab] 'hippie-expand)

     In the interest of maintaining a single consistent set of key
     bindings between X and tty emacsen you may want to make equivalent
     X keystroke generate "backtab" as well, you can do this by doing
     this:

     (define-key function-key-map [S-tab] [backtab]) or (define-key
     function-key-map [iso-lefttab] [backtab])

     To make S-tab or whatever keystroke you made generate backtab on a
     terminal be recognized as backtab under X11 as well. You can check
     how Emacs recognizes this keystroke currently by doing C-h c
     <keystroke>.