This is ./gdb.info, produced by makeinfo version 4.0b from gdb.texinfo.

INFO-DIR-SECTION Programming & development tools.
START-INFO-DIR-ENTRY
* Gdb: (gdb).                     The GNU debugger.
END-INFO-DIR-ENTRY

   This file documents the GNU debugger GDB.

   This is the Ninth Edition, January 2002, of `Debugging with GDB: the
GNU Source-Level Debugger' for GDB Version 5.1.1.

   Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996,
1998,
1999, 2000, 2001, 2002 Free Software Foundation, Inc.

   Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.1 or
any later version published by the Free Software Foundation; with the
Invariant Sections being "Free Software" and "Free Software Needs Free
Documentation", with the Front-Cover Texts being "A GNU Manual," and
with the Back-Cover Texts as in (a) below.

   (a) The Free Software Foundation's Back-Cover Text is: "You have
freedom to copy and modify this GNU Manual, like GNU software.  Copies
published by the Free Software Foundation raise funds for GNU
development."


File: gdb.info,  Node: Command Line Editing,  Next: Using History Interactively,  Prev: Formatting Documentation,  Up: Top

Command Line Editing
********************

   This chapter describes the basic features of the GNU command line
editing interface.

* Menu:

* Introduction and Notation::	Notation used in this text.
* Readline Interaction::	The minimum set of commands for editing a line.
* Readline Init File::		Customizing Readline from a user's view.
* Bindable Readline Commands::	A description of most of the Readline commands
				available for binding
* Readline vi Mode::		A short description of how to make Readline
				behave like the vi editor.


File: gdb.info,  Node: Introduction and Notation,  Next: Readline Interaction,  Up: Command Line Editing

Introduction to Line Editing
============================

   The following paragraphs describe the notation used to represent
keystrokes.

   The text <C-k> is read as `Control-K' and describes the character
produced when the <k> key is pressed while the Control key is depressed.

   The text <M-k> is read as `Meta-K' and describes the character
produced when the Meta key (if you have one) is depressed, and the <k>
key is pressed.  The Meta key is labeled <ALT> on many keyboards.  On
keyboards with two keys labeled <ALT> (usually to either side of the
space bar), the <ALT> on the left side is generally set to work as a
Meta key.  The <ALT> key on the right may also be configured to work as
a Meta key or may be configured as some other modifier, such as a
Compose key for typing accented characters.

   If you do not have a Meta or <ALT> key, or another key working as a
Meta key, the identical keystroke can be generated by typing <ESC>
first, and then typing <k>.  Either process is known as "metafying" the
<k> key.

   The text <M-C-k> is read as `Meta-Control-k' and describes the
character produced by "metafying" <C-k>.

   In addition, several keys have their own names.  Specifically,
<DEL>, <ESC>, <LFD>, <SPC>, <RET>, and <TAB> all stand for themselves
when seen in this text, or in an init file (*note Readline Init File::).
If your keyboard lacks a <LFD> key, typing <C-j> will produce the
desired character.  The <RET> key may be labeled <Return> or <Enter> on
some keyboards.


File: gdb.info,  Node: Readline Interaction,  Next: Readline Init File,  Prev: Introduction and Notation,  Up: Command Line Editing

Readline Interaction
====================

   Often during an interactive session you type in a long line of text,
only to notice that the first word on the line is misspelled.  The
Readline library gives you a set of commands for manipulating the text
as you type it in, allowing you to just fix your typo, and not forcing
you to retype the majority of the line.  Using these editing commands,
you move the cursor to the place that needs correction, and delete or
insert the text of the corrections.  Then, when you are satisfied with
the line, you simply press <RETURN>.  You do not have to be at the end
of the line to press <RETURN>; the entire line is accepted regardless
of the location of the cursor within the line.

* Menu:

* Readline Bare Essentials::	The least you need to know about Readline.
* Readline Movement Commands::	Moving about the input line.
* Readline Killing Commands::	How to delete text, and how to get it back!
* Readline Arguments::		Giving numeric arguments to commands.
* Searching::			Searching through previous lines.


File: gdb.info,  Node: Readline Bare Essentials,  Next: Readline Movement Commands,  Up: Readline Interaction

Readline Bare Essentials
------------------------

   In order to enter characters into the line, simply type them.  The
typed character appears where the cursor was, and then the cursor moves
one space to the right.  If you mistype a character, you can use your
erase character to back up and delete the mistyped character.

   Sometimes you may mistype a character, and not notice the error
until you have typed several other characters.  In that case, you can
type <C-b> to move the cursor to the left, and then correct your
mistake.  Afterwards, you can move the cursor to the right with <C-f>.

   When you add text in the middle of a line, you will notice that
characters to the right of the cursor are `pushed over' to make room
for the text that you have inserted.  Likewise, when you delete text
behind the cursor, characters to the right of the cursor are `pulled
back' to fill in the blank space created by the removal of the text.  A
list of the bare essentials for editing the text of an input line
follows.

<C-b>
     Move back one character.

<C-f>
     Move forward one character.

<DEL> or <Backspace>
     Delete the character to the left of the cursor.

<C-d>
     Delete the character underneath the cursor.

Printing characters
     Insert the character into the line at the cursor.

<C-_> or <C-x C-u>
     Undo the last editing command.  You can undo all the way back to an
     empty line.

(Depending on your configuration, the <Backspace> key be set to delete
the character to the left of the cursor and the <DEL> key set to delete
the character underneath the cursor, like <C-d>, rather than the
character to the left of the cursor.)


File: gdb.info,  Node: Readline Movement Commands,  Next: Readline Killing Commands,  Prev: Readline Bare Essentials,  Up: Readline Interaction

Readline Movement Commands
--------------------------

   The above table describes the most basic keystrokes that you need in
order to do editing of the input line.  For your convenience, many
other commands have been added in addition to <C-b>, <C-f>, <C-d>, and
<DEL>.  Here are some commands for moving more rapidly about the line.

<C-a>
     Move to the start of the line.

<C-e>
     Move to the end of the line.

<M-f>
     Move forward a word, where a word is composed of letters and
     digits.

<M-b>
     Move backward a word.

<C-l>
     Clear the screen, reprinting the current line at the top.

   Notice how <C-f> moves forward a character, while <M-f> moves
forward a word.  It is a loose convention that control keystrokes
operate on characters while meta keystrokes operate on words.


File: gdb.info,  Node: Readline Killing Commands,  Next: Readline Arguments,  Prev: Readline Movement Commands,  Up: Readline Interaction

Readline Killing Commands
-------------------------

   "Killing" text means to delete the text from the line, but to save
it away for later use, usually by "yanking" (re-inserting) it back into
the line.  (`Cut' and `paste' are more recent jargon for `kill' and
`yank'.)

   If the description for a command says that it `kills' text, then you
can be sure that you can get the text back in a different (or the same)
place later.

   When you use a kill command, the text is saved in a "kill-ring".
Any number of consecutive kills save all of the killed text together, so
that when you yank it back, you get it all.  The kill ring is not line
specific; the text that you killed on a previously typed line is
available to be yanked back later, when you are typing another line.

   Here is the list of commands for killing text.

<C-k>
     Kill the text from the current cursor position to the end of the
     line.

<M-d>
     Kill from the cursor to the end of the current word, or, if between
     words, to the end of the next word.  Word boundaries are the same
     as those used by <M-f>.

<M-DEL>
     Kill from the cursor the start of the previous word, or, if between
     words, to the start of the previous word.  Word boundaries are the
     same as those used by <M-b>.

<C-w>
     Kill from the cursor to the previous whitespace.  This is
     different than <M-DEL> because the word boundaries differ.

   Here is how to "yank" the text back into the line.  Yanking means to
copy the most-recently-killed text from the kill buffer.

<C-y>
     Yank the most recently killed text back into the buffer at the
     cursor.

<M-y>
     Rotate the kill-ring, and yank the new top.  You can only do this
     if the prior command is <C-y> or <M-y>.


File: gdb.info,  Node: Readline Arguments,  Next: Searching,  Prev: Readline Killing Commands,  Up: Readline Interaction

Readline Arguments
------------------

   You can pass numeric arguments to Readline commands.  Sometimes the
argument acts as a repeat count, other times it is the sign of the
argument that is significant.  If you pass a negative argument to a
command which normally acts in a forward direction, that command will
act in a backward direction.  For example, to kill text back to the
start of the line, you might type `M-- C-k'.

   The general way to pass numeric arguments to a command is to type
meta digits before the command.  If the first `digit' typed is a minus
sign (`-'), then the sign of the argument will be negative.  Once you
have typed one meta digit to get the argument started, you can type the
remainder of the digits, and then the command.  For example, to give
the <C-d> command an argument of 10, you could type `M-1 0 C-d'.


File: gdb.info,  Node: Searching,  Prev: Readline Arguments,  Up: Readline Interaction

Searching for Commands in the History
-------------------------------------

   Readline provides commands for searching through the command history
for lines containing a specified string.  There are two search modes:
INCREMENTAL and NON-INCREMENTAL.

   Incremental searches begin before the user has finished typing the
search string.  As each character of the search string is typed,
Readline displays the next entry from the history matching the string
typed so far.  An incremental search requires only as many characters
as needed to find the desired history entry.  To search backward in the
history for a particular string, type <C-r>.  Typing <C-s> searches
forward through the history.  The characters present in the value of
the `isearch-terminators' variable are used to terminate an incremental
search.  If that variable has not been assigned a value, the <ESC> and
<C-J> characters will terminate an incremental search.  <C-g> will
abort an incremental search and restore the original line.  When the
search is terminated, the history entry containing the search string
becomes the current line.

   To find other matching entries in the history list, type <C-r> or
<C-s> as appropriate.  This will search backward or forward in the
history for the next entry matching the search string typed so far.
Any other key sequence bound to a Readline command will terminate the
search and execute that command.  For instance, a <RET> will terminate
the search and accept the line, thereby executing the command from the
history list.

   Non-incremental searches read the entire search string before
starting to search for matching history lines.  The search string may be
typed by the user or be part of the contents of the current line.


File: gdb.info,  Node: Readline Init File,  Next: Bindable Readline Commands,  Prev: Readline Interaction,  Up: Command Line Editing

Readline Init File
==================

   Although the Readline library comes with a set of Emacs-like
keybindings installed by default, it is possible to use a different set
of keybindings.  Any user can customize programs that use Readline by
putting commands in an "inputrc" file, conventionally in his home
directory.  The name of this file is taken from the value of the
environment variable `INPUTRC'.  If that variable is unset, the default
is `~/.inputrc'.

   When a program which uses the Readline library starts up, the init
file is read, and the key bindings are set.

   In addition, the `C-x C-r' command re-reads this init file, thus
incorporating any changes that you might have made to it.

* Menu:

* Readline Init File Syntax::	Syntax for the commands in the inputrc file.

* Conditional Init Constructs::	Conditional key bindings in the inputrc file.

* Sample Init File::		An example inputrc file.


File: gdb.info,  Node: Readline Init File Syntax,  Next: Conditional Init Constructs,  Up: Readline Init File

Readline Init File Syntax
-------------------------

   There are only a few basic constructs allowed in the Readline init
file.  Blank lines are ignored.  Lines beginning with a `#' are
comments.  Lines beginning with a `$' indicate conditional constructs
(*note Conditional Init Constructs::).  Other lines denote variable
settings and key bindings.

Variable Settings
     You can modify the run-time behavior of Readline by altering the
     values of variables in Readline using the `set' command within the
     init file.  Here is how to change from the default Emacs-like key
     binding to use `vi' line editing commands:

          set editing-mode vi

     A great deal of run-time behavior is changeable with the following
     variables.

    `bell-style'
          Controls what happens when Readline wants to ring the
          terminal bell.  If set to `none', Readline never rings the
          bell.  If set to `visible', Readline uses a visible bell if
          one is available.  If set to `audible' (the default),
          Readline attempts to ring the terminal's bell.

    `comment-begin'
          The string to insert at the beginning of the line when the
          `insert-comment' command is executed.  The default value is
          `"#"'.

    `completion-ignore-case'
          If set to `on', Readline performs filename matching and
          completion in a case-insensitive fashion.  The default value
          is `off'.

    `completion-query-items'
          The number of possible completions that determines when the
          user is asked whether he wants to see the list of
          possibilities.  If the number of possible completions is
          greater than this value, Readline will ask the user whether
          or not he wishes to view them; otherwise, they are simply
          listed.  The default limit is `100'.

    `convert-meta'
          If set to `on', Readline will convert characters with the
          eighth bit set to an ASCII key sequence by stripping the
          eighth bit and prefixing an <ESC> character, converting them
          to a meta-prefixed key sequence.  The default value is `on'.

    `disable-completion'
          If set to `On', Readline will inhibit word completion.
          Completion  characters will be inserted into the line as if
          they had been mapped to `self-insert'.  The default is `off'.

    `editing-mode'
          The `editing-mode' variable controls which default set of key
          bindings is used.  By default, Readline starts up in Emacs
          editing mode, where the keystrokes are most similar to Emacs.
          This variable can be set to either `emacs' or `vi'.

    `enable-keypad'
          When set to `on', Readline will try to enable the application
          keypad when it is called.  Some systems need this to enable
          the arrow keys.  The default is `off'.

    `expand-tilde'
          If set to `on', tilde expansion is performed when Readline
          attempts word completion.  The default is `off'.

    `horizontal-scroll-mode'
          This variable can be set to either `on' or `off'.  Setting it
          to `on' means that the text of the lines being edited will
          scroll horizontally on a single screen line when they are
          longer than the width of the screen, instead of wrapping onto
          a new screen line.  By default, this variable is set to `off'.

    `input-meta'
          If set to `on', Readline will enable eight-bit input (it will
          not strip the eighth bit from the characters it reads),
          regardless of what the terminal claims it can support.  The
          default value is `off'.  The name `meta-flag' is a synonym
          for this variable.

    `isearch-terminators'
          The string of characters that should terminate an incremental
          search without subsequently executing the character as a
          command (*note Searching::).  If this variable has not been
          given a value, the characters <ESC> and <C-J> will terminate
          an incremental search.

    `keymap'
          Sets Readline's idea of the current keymap for key binding
          commands.  Acceptable `keymap' names are `emacs',
          `emacs-standard', `emacs-meta', `emacs-ctlx', `vi',
          `vi-command', and `vi-insert'.  `vi' is equivalent to
          `vi-command'; `emacs' is equivalent to `emacs-standard'.  The
          default value is `emacs'.  The value of the `editing-mode'
          variable also affects the default keymap.

    `mark-directories'
          If set to `on', completed directory names have a slash
          appended.  The default is `on'.

    `mark-modified-lines'
          This variable, when set to `on', causes Readline to display an
          asterisk (`*') at the start of history lines which have been
          modified.  This variable is `off' by default.

    `output-meta'
          If set to `on', Readline will display characters with the
          eighth bit set directly rather than as a meta-prefixed escape
          sequence.  The default is `off'.

    `print-completions-horizontally'
          If set to `on', Readline will display completions with matches
          sorted horizontally in alphabetical order, rather than down
          the screen.  The default is `off'.

    `show-all-if-ambiguous'
          This alters the default behavior of the completion functions.
          If set to `on', words which have more than one possible
          completion cause the matches to be listed immediately instead
          of ringing the bell.  The default value is `off'.

    `visible-stats'
          If set to `on', a character denoting a file's type is
          appended to the filename when listing possible completions.
          The default is `off'.

Key Bindings
     The syntax for controlling key bindings in the init file is
     simple.  First you need to find the name of the command that you
     want to change.  The following sections contain tables of the
     command name, the default keybinding, if any, and a short
     description of what the command does.

     Once you know the name of the command, simply place the name of
     the key you wish to bind the command to, a colon, and then the
     name of the command on a line in the init file.  The name of the
     key can be expressed in different ways, depending on which is most
     comfortable for you.

    KEYNAME: FUNCTION-NAME or MACRO
          KEYNAME is the name of a key spelled out in English.  For
          example:
               Control-u: universal-argument
               Meta-Rubout: backward-kill-word
               Control-o: "> output"

          In the above example, <C-u> is bound to the function
          `universal-argument', and <C-o> is bound to run the macro
          expressed on the right hand side (that is, to insert the text
          `> output' into the line).

    "KEYSEQ": FUNCTION-NAME or MACRO
          KEYSEQ differs from KEYNAME above in that strings denoting an
          entire key sequence can be specified, by placing the key
          sequence in double quotes.  Some GNU Emacs style key escapes
          can be used, as in the following example, but the special
          character names are not recognized.

               "\C-u": universal-argument
               "\C-x\C-r": re-read-init-file
               "\e[11~": "Function Key 1"

          In the above example, <C-u> is bound to the function
          `universal-argument' (just as it was in the first example),
          `<C-x> <C-r>' is bound to the function `re-read-init-file',
          and `<ESC> <[> <1> <1> <~>' is bound to insert the text
          `Function Key 1'.

     The following GNU Emacs style escape sequences are available when
     specifying key sequences:

    `\C-'
          control prefix

    `\M-'
          meta prefix

    `\e'
          an escape character

    `\\'
          backslash

    `\"'
          <">, a double quotation mark

    `\''
          <'>, a single quote or apostrophe

     In addition to the GNU Emacs style escape sequences, a second set
     of backslash escapes is available:

    `\a'
          alert (bell)

    `\b'
          backspace

    `\d'
          delete

    `\f'
          form feed

    `\n'
          newline

    `\r'
          carriage return

    `\t'
          horizontal tab

    `\v'
          vertical tab

    `\NNN'
          the character whose `ASCII' code is the octal value NNN (one
          to three digits)

    `\xNNN'
          the character whose `ASCII' code is the hexadecimal value NNN
          (one to three digits)

     When entering the text of a macro, single or double quotes must be
     used to indicate a macro definition.  Unquoted text is assumed to
     be a function name.  In the macro body, the backslash escapes
     described above are expanded.  Backslash will quote any other
     character in the macro text, including `"' and `''.  For example,
     the following binding will make `C-x \' insert a single `\' into
     the line:
          "\C-x\\": "\\"


File: gdb.info,  Node: Conditional Init Constructs,  Next: Sample Init File,  Prev: Readline Init File Syntax,  Up: Readline Init File

Conditional Init Constructs
---------------------------

   Readline implements a facility similar in spirit to the conditional
compilation features of the C preprocessor which allows key bindings
and variable settings to be performed as the result of tests.  There
are four parser directives used.

`$if'
     The `$if' construct allows bindings to be made based on the
     editing mode, the terminal being used, or the application using
     Readline.  The text of the test extends to the end of the line; no
     characters are required to isolate it.

    `mode'
          The `mode=' form of the `$if' directive is used to test
          whether Readline is in `emacs' or `vi' mode.  This may be
          used in conjunction with the `set keymap' command, for
          instance, to set bindings in the `emacs-standard' and
          `emacs-ctlx' keymaps only if Readline is starting out in
          `emacs' mode.

    `term'
          The `term=' form may be used to include terminal-specific key
          bindings, perhaps to bind the key sequences output by the
          terminal's function keys.  The word on the right side of the
          `=' is tested against both the full name of the terminal and
          the portion of the terminal name before the first `-'.  This
          allows `sun' to match both `sun' and `sun-cmd', for instance.

    `application'
          The APPLICATION construct is used to include
          application-specific settings.  Each program using the
          Readline library sets the APPLICATION NAME, and you can test
          for it.  This could be used to bind key sequences to
          functions useful for a specific program.  For instance, the
          following command adds a key sequence that quotes the current
          or previous word in Bash:
               $if Bash
               # Quote the current or previous word
               "\C-xq": "\eb\"\ef\""
               $endif

`$endif'
     This command, as seen in the previous example, terminates an `$if'
     command.

`$else'
     Commands in this branch of the `$if' directive are executed if the
     test fails.

`$include'
     This directive takes a single filename as an argument and reads
     commands and bindings from that file.
          $include /etc/inputrc


File: gdb.info,  Node: Sample Init File,  Prev: Conditional Init Constructs,  Up: Readline Init File

Sample Init File
----------------

   Here is an example of an inputrc file.  This illustrates key
binding, variable assignment, and conditional syntax.


     # This file controls the behaviour of line input editing for
     # programs that use the Gnu Readline library.  Existing programs
     # include FTP, Bash, and Gdb.
     #
     # You can re-read the inputrc file with C-x C-r.
     # Lines beginning with '#' are comments.
     #
     # First, include any systemwide bindings and variable assignments from
     # /etc/Inputrc
     $include /etc/Inputrc
     
     #
     # Set various bindings for emacs mode.
     
     set editing-mode emacs
     
     $if mode=emacs
     
     Meta-Control-h:	backward-kill-word	Text after the function name is ignored
     
     #
     # Arrow keys in keypad mode
     #
     #"\M-OD":        backward-char
     #"\M-OC":        forward-char
     #"\M-OA":        previous-history
     #"\M-OB":        next-history
     #
     # Arrow keys in ANSI mode
     #
     "\M-[D":        backward-char
     "\M-[C":        forward-char
     "\M-[A":        previous-history
     "\M-[B":        next-history
     #
     # Arrow keys in 8 bit keypad mode
     #
     #"\M-\C-OD":       backward-char
     #"\M-\C-OC":       forward-char
     #"\M-\C-OA":       previous-history
     #"\M-\C-OB":       next-history
     #
     # Arrow keys in 8 bit ANSI mode
     #
     #"\M-\C-[D":       backward-char
     #"\M-\C-[C":       forward-char
     #"\M-\C-[A":       previous-history
     #"\M-\C-[B":       next-history
     
     C-q: quoted-insert
     
     $endif
     
     # An old-style binding.  This happens to be the default.
     TAB: complete
     
     # Macros that are convenient for shell interaction
     $if Bash
     # edit the path
     "\C-xp": "PATH=${PATH}\e\C-e\C-a\ef\C-f"
     # prepare to type a quoted word -- insert open and close
     # double quotes and move to just after the open quote
     "\C-x\"": "\"\"\C-b"
     # insert a backslash (testing backslash escapes in sequences
     # and macros)
     "\C-x\\": "\\"
     # Quote the current or previous word
     "\C-xq": "\eb\"\ef\""
     # Add a binding to refresh the line, which is unbound
     "\C-xr": redraw-current-line
     # Edit variable on current line.
     "\M-\C-v": "\C-a\C-k$\C-y\M-\C-e\C-a\C-y="
     $endif
     
     # use a visible bell if one is available
     set bell-style visible
     
     # don't strip characters to 7 bits when reading
     set input-meta on
     
     # allow iso-latin1 characters to be inserted rather than converted to
     # prefix-meta sequences
     set convert-meta off
     
     # display characters with the eighth bit set directly rather than
     # as meta-prefixed characters
     set output-meta on
     
     # if there are more than 150 possible completions for a word, ask the
     # user if he wants to see all of them
     set completion-query-items 150
     
     # For FTP
     $if Ftp
     "\C-xg": "get \M-?"
     "\C-xt": "put \M-?"
     "\M-.": yank-last-arg
     $endif


File: gdb.info,  Node: Bindable Readline Commands,  Next: Readline vi Mode,  Prev: Readline Init File,  Up: Command Line Editing

Bindable Readline Commands
==========================

* Menu:

* Commands For Moving::		Moving about the line.
* Commands For History::	Getting at previous lines.
* Commands For Text::		Commands for changing text.
* Commands For Killing::	Commands for killing and yanking.
* Numeric Arguments::		Specifying numeric arguments, repeat counts.
* Commands For Completion::	Getting Readline to do the typing for you.
* Keyboard Macros::		Saving and re-executing typed characters
* Miscellaneous Commands::	Other miscellaneous commands.

   This section describes Readline commands that may be bound to key
sequences.

   Command names without an accompanying key sequence are unbound by
default.  In the following descriptions, POINT refers to the current
cursor position, and MARK refers to a cursor position saved by the
`set-mark' command.  The text between the point and mark is referred to
as the REGION.


File: gdb.info,  Node: Commands For Moving,  Next: Commands For History,  Up: Bindable Readline Commands

Commands For Moving
-------------------

`beginning-of-line (C-a)'
     Move to the start of the current line.

`end-of-line (C-e)'
     Move to the end of the line.

`forward-char (C-f)'
     Move forward a character.

`backward-char (C-b)'
     Move back a character.

`forward-word (M-f)'
     Move forward to the end of the next word.  Words are composed of
     letters and digits.

`backward-word (M-b)'
     Move back to the start of the current or previous word.  Words are
     composed of letters and digits.

`clear-screen (C-l)'
     Clear the screen and redraw the current line, leaving the current
     line at the top of the screen.

`redraw-current-line ()'
     Refresh the current line.  By default, this is unbound.


File: gdb.info,  Node: Commands For History,  Next: Commands For Text,  Prev: Commands For Moving,  Up: Bindable Readline Commands

Commands For Manipulating The History
-------------------------------------

`accept-line (Newline, Return)'
     Accept the line regardless of where the cursor is.  If this line is
     non-empty, add it to the history list.  If this line was a history
     line, then restore the history line to its original state.

`previous-history (C-p)'
     Move `up' through the history list.

`next-history (C-n)'
     Move `down' through the history list.

`beginning-of-history (M-<)'
     Move to the first line in the history.

`end-of-history (M->)'
     Move to the end of the input history, i.e., the line currently
     being entered.

`reverse-search-history (C-r)'
     Search backward starting at the current line and moving `up'
     through the history as necessary.  This is an incremental search.

`forward-search-history (C-s)'
     Search forward starting at the current line and moving `down'
     through the the history as necessary.  This is an incremental
     search.

`non-incremental-reverse-search-history (M-p)'
     Search backward starting at the current line and moving `up'
     through the history as necessary using a non-incremental search
     for a string supplied by the user.

`non-incremental-forward-search-history (M-n)'
     Search forward starting at the current line and moving `down'
     through the the history as necessary using a non-incremental search
     for a string supplied by the user.

`history-search-forward ()'
     Search forward through the history for the string of characters
     between the start of the current line and the point.  This is a
     non-incremental search.  By default, this command is unbound.

`history-search-backward ()'
     Search backward through the history for the string of characters
     between the start of the current line and the point.  This is a
     non-incremental search.  By default, this command is unbound.

`yank-nth-arg (M-C-y)'
     Insert the first argument to the previous command (usually the
     second word on the previous line).  With an argument N, insert the
     Nth word from the previous command (the words in the previous
     command begin with word 0).  A negative argument inserts the Nth
     word from the end of the previous command.

`yank-last-arg (M-., M-_)'
     Insert last argument to the previous command (the last word of the
     previous history entry).  With an argument, behave exactly like
     `yank-nth-arg'.  Successive calls to `yank-last-arg' move back
     through the history list, inserting the last argument of each line
     in turn.


File: gdb.info,  Node: Commands For Text,  Next: Commands For Killing,  Prev: Commands For History,  Up: Bindable Readline Commands

Commands For Changing Text
--------------------------

`delete-char (C-d)'
     Delete the character under the cursor.  If the cursor is at the
     beginning of the line, there are no characters in the line, and
     the last character typed was not bound to `delete-char', then
     return `EOF'.

`backward-delete-char (Rubout)'
     Delete the character behind the cursor.  A numeric argument means
     to kill the characters instead of deleting them.

`forward-backward-delete-char ()'
     Delete the character under the cursor, unless the cursor is at the
     end of the line, in which case the character behind the cursor is
     deleted.  By default, this is not bound to a key.

`quoted-insert (C-q, C-v)'
     Add the next character typed to the line verbatim.  This is how to
     insert key sequences like <C-q>, for example.

`tab-insert (M-TAB)'
     Insert a tab character.

`self-insert (a, b, A, 1, !, ...)'
     Insert yourself.

`transpose-chars (C-t)'
     Drag the character before the cursor forward over the character at
     the cursor, moving the cursor forward as well.  If the insertion
     point is at the end of the line, then this transposes the last two
     characters of the line.  Negative arguments have no effect.

`transpose-words (M-t)'
     Drag the word before point past the word after point, moving point
     past that word as well.

`upcase-word (M-u)'
     Uppercase the current (or following) word.  With a negative
     argument, uppercase the previous word, but do not move the cursor.

`downcase-word (M-l)'
     Lowercase the current (or following) word.  With a negative
     argument, lowercase the previous word, but do not move the cursor.

`capitalize-word (M-c)'
     Capitalize the current (or following) word.  With a negative
     argument, capitalize the previous word, but do not move the cursor.


File: gdb.info,  Node: Commands For Killing,  Next: Numeric Arguments,  Prev: Commands For Text,  Up: Bindable Readline Commands

Killing And Yanking
-------------------

`kill-line (C-k)'
     Kill the text from point to the end of the line.

`backward-kill-line (C-x Rubout)'
     Kill backward to the beginning of the line.

`unix-line-discard (C-u)'
     Kill backward from the cursor to the beginning of the current line.

`kill-whole-line ()'
     Kill all characters on the current line, no matter point is.  By
     default, this is unbound.

`kill-word (M-d)'
     Kill from point to the end of the current word, or if between
     words, to the end of the next word.  Word boundaries are the same
     as `forward-word'.

`backward-kill-word (M-DEL)'
     Kill the word behind point.  Word boundaries are the same as
     `backward-word'.

`unix-word-rubout (C-w)'
     Kill the word behind point, using white space as a word boundary.
     The killed text is saved on the kill-ring.

`delete-horizontal-space ()'
     Delete all spaces and tabs around point.  By default, this is
     unbound.

`kill-region ()'
     Kill the text in the current region.  By default, this command is
     unbound.

`copy-region-as-kill ()'
     Copy the text in the region to the kill buffer, so it can be yanked
     right away.  By default, this command is unbound.

`copy-backward-word ()'
     Copy the word before point to the kill buffer.  The word
     boundaries are the same as `backward-word'.  By default, this
     command is unbound.

`copy-forward-word ()'
     Copy the word following point to the kill buffer.  The word
     boundaries are the same as `forward-word'.  By default, this
     command is unbound.

`yank (C-y)'
     Yank the top of the kill ring into the buffer at the current
     cursor position.

`yank-pop (M-y)'
     Rotate the kill-ring, and yank the new top.  You can only do this
     if the prior command is yank or yank-pop.


File: gdb.info,  Node: Numeric Arguments,  Next: Commands For Completion,  Prev: Commands For Killing,  Up: Bindable Readline Commands

Specifying Numeric Arguments
----------------------------

`digit-argument (M-0, M-1, ... M--)'
     Add this digit to the argument already accumulating, or start a new
     argument.  <M-> starts a negative argument.

`universal-argument ()'
     This is another way to specify an argument.  If this command is
     followed by one or more digits, optionally with a leading minus
     sign, those digits define the argument.  If the command is
     followed by digits, executing `universal-argument' again ends the
     numeric argument, but is otherwise ignored.  As a special case, if
     this command is immediately followed by a character that is
     neither a digit or minus sign, the argument count for the next
     command is multiplied by four.  The argument count is initially
     one, so executing this function the first time makes the argument
     count four, a second time makes the argument count sixteen, and so
     on.  By default, this is not bound to a key.


File: gdb.info,  Node: Commands For Completion,  Next: Keyboard Macros,  Prev: Numeric Arguments,  Up: Bindable Readline Commands

Letting Readline Type For You
-----------------------------

`complete (TAB)'
     Attempt to do completion on the text before the cursor.  This is
     application-specific.  Generally, if you are typing a filename
     argument, you can do filename completion; if you are typing a
     command, you can do command completion; if you are typing in a
     symbol to GDB, you can do symbol name completion; if you are
     typing in a variable to Bash, you can do variable name completion,
     and so on.

`possible-completions (M-?)'
     List the possible completions of the text before the cursor.

`insert-completions (M-*)'
     Insert all completions of the text before point that would have
     been generated by `possible-completions'.

`menu-complete ()'
     Similar to `complete', but replaces the word to be completed with
     a single match from the list of possible completions.  Repeated
     execution of `menu-complete' steps through the list of possible
     completions, inserting each match in turn.  At the end of the list
     of completions, the bell is rung and the original text is restored.
     An argument of N moves N positions forward in the list of matches;
     a negative argument may be used to move backward through the list.
     This command is intended to be bound to `TAB', but is unbound by
     default.

`delete-char-or-list ()'
     Deletes the character under the cursor if not at the beginning or
     end of the line (like `delete-char').  If at the end of the line,
     behaves identically to `possible-completions'.  This command is
     unbound by default.


File: gdb.info,  Node: Keyboard Macros,  Next: Miscellaneous Commands,  Prev: Commands For Completion,  Up: Bindable Readline Commands

Keyboard Macros
---------------

`start-kbd-macro (C-x ()'
     Begin saving the characters typed into the current keyboard macro.

`end-kbd-macro (C-x ))'
     Stop saving the characters typed into the current keyboard macro
     and save the definition.

`call-last-kbd-macro (C-x e)'
     Re-execute the last keyboard macro defined, by making the
     characters in the macro appear as if typed at the keyboard.


File: gdb.info,  Node: Miscellaneous Commands,  Prev: Keyboard Macros,  Up: Bindable Readline Commands

Some Miscellaneous Commands
---------------------------

`re-read-init-file (C-x C-r)'
     Read in the contents of the INPUTRC file, and incorporate any
     bindings or variable assignments found there.

`abort (C-g)'
     Abort the current editing command and ring the terminal's bell
     (subject to the setting of `bell-style').

`do-uppercase-version (M-a, M-b, M-X, ...)'
     If the metafied character X is lowercase, run the command that is
     bound to the corresponding uppercase character.

`prefix-meta (ESC)'
     Make the next character typed be metafied.  This is for keyboards
     without a meta key.  Typing `ESC f' is equivalent to typing `M-f'.

`undo (C-_, C-x C-u)'
     Incremental undo, separately remembered for each line.

`revert-line (M-r)'
     Undo all changes made to this line.  This is like executing the
     `undo' command enough times to get back to the beginning.

`tilde-expand (M-~)'
     Perform tilde expansion on the current word.

`set-mark (C-@)'
     Set the mark to the current point.  If a numeric argument is
     supplied, the mark is set to that position.

`exchange-point-and-mark (C-x C-x)'
     Swap the point with the mark.  The current cursor position is set
     to the saved position, and the old cursor position is saved as the
     mark.

`character-search (C-])'
     A character is read and point is moved to the next occurrence of
     that character.  A negative count searches for previous
     occurrences.

`character-search-backward (M-C-])'
     A character is read and point is moved to the previous occurrence
     of that character.  A negative count searches for subsequent
     occurrences.

`insert-comment (M-#)'
     The value of the `comment-begin' variable is inserted at the
     beginning of the current line, and the line is accepted as if a
     newline had been typed.

`dump-functions ()'
     Print all of the functions and their key bindings to the Readline
     output stream.  If a numeric argument is supplied, the output is
     formatted in such a way that it can be made part of an INPUTRC
     file.  This command is unbound by default.

`dump-variables ()'
     Print all of the settable variables and their values to the
     Readline output stream.  If a numeric argument is supplied, the
     output is formatted in such a way that it can be made part of an
     INPUTRC file.  This command is unbound by default.

`dump-macros ()'
     Print all of the Readline key sequences bound to macros and the
     strings they ouput.  If a numeric argument is supplied, the output
     is formatted in such a way that it can be made part of an INPUTRC
     file.  This command is unbound by default.


File: gdb.info,  Node: Readline vi Mode,  Prev: Bindable Readline Commands,  Up: Command Line Editing

Readline vi Mode
================

   While the Readline library does not have a full set of `vi' editing
functions, it does contain enough to allow simple editing of the line.
The Readline `vi' mode behaves as specified in the POSIX 1003.2
standard.

   In order to switch interactively between `emacs' and `vi' editing
modes, use the command M-C-j (toggle-editing-mode).  The Readline
default is `emacs' mode.

   When you enter a line in `vi' mode, you are already placed in
`insertion' mode, as if you had typed an `i'.  Pressing <ESC> switches
you into `command' mode, where you can edit the text of the line with
the standard `vi' movement keys, move to previous history lines with
`k' and subsequent lines with `j', and so forth.


File: gdb.info,  Node: Using History Interactively,  Next: Installing GDB,  Prev: Command Line Editing,  Up: Top

Using History Interactively
***************************

   This chapter describes how to use the GNU History Library
interactively, from a user's standpoint.  It should be considered a
user's guide.

* Menu:

* History Interaction::		What it feels like using History as a user.


File: gdb.info,  Node: History Interaction,  Up: Using History Interactively

History Expansion
=================

   The History library provides a history expansion feature that is
similar to the history expansion provided by `csh'.  This section
describes the syntax used to manipulate the history information.

   History expansions introduce words from the history list into the
input stream, making it easy to repeat commands, insert the arguments
to a previous command into the current input line, or fix errors in
previous commands quickly.

   History expansion takes place in two parts.  The first is to
determine which line from the history list should be used during
substitution.  The second is to select portions of that line for
inclusion into the current one.  The line selected from the history is
called the "event", and the portions of that line that are acted upon
are called "words".  Various "modifiers" are available to manipulate
the selected words.  The line is broken into words in the same fashion
that Bash does, so that several words surrounded by quotes are
considered one word.  History expansions are introduced by the
appearance of the history expansion character, which is `!' by default.

* Menu:

* Event Designators::	How to specify which history line to use.
* Word Designators::	Specifying which words are of interest.
* Modifiers::		Modifying the results of substitution.


File: gdb.info,  Node: Event Designators,  Next: Word Designators,  Up: History Interaction

Event Designators
-----------------

   An event designator is a reference to a command line entry in the
history list.

`!'
     Start a history substitution, except when followed by a space, tab,
     the end of the line, `=' or `('.

`!N'
     Refer to command line N.

`!-N'
     Refer to the command N lines back.

`!!'
     Refer to the previous command.  This is a synonym for `!-1'.

`!STRING'
     Refer to the most recent command starting with STRING.

`!?STRING[?]'
     Refer to the most recent command containing STRING.  The trailing
     `?' may be omitted if the STRING is followed immediately by a
     newline.

`^STRING1^STRING2^'
     Quick Substitution.  Repeat the last command, replacing STRING1
     with STRING2.  Equivalent to `!!:s/STRING1/STRING2/'.

`!#'
     The entire command line typed so far.


File: gdb.info,  Node: Word Designators,  Next: Modifiers,  Prev: Event Designators,  Up: History Interaction

Word Designators
----------------

   Word designators are used to select desired words from the event.  A
`:' separates the event specification from the word designator.  It may
be omitted if the word designator begins with a `^', `$', `*', `-', or
`%'.  Words are numbered from the beginning of the line, with the first
word being denoted by 0 (zero).  Words are inserted into the current
line separated by single spaces.

   For example,

`!!'
     designates the preceding command.  When you type this, the
     preceding command is repeated in toto.

`!!:$'
     designates the last argument of the preceding command.  This may be
     shortened to `!$'.

`!fi:2'
     designates the second argument of the most recent command starting
     with the letters `fi'.

   Here are the word designators:

`0 (zero)'
     The `0'th word.  For many applications, this is the command word.

`N'
     The Nth word.

`^'
     The first argument; that is, word 1.

`$'
     The last argument.

`%'
     The word matched by the most recent `?STRING?' search.

`X-Y'
     A range of words; `-Y' abbreviates `0-Y'.

`*'
     All of the words, except the `0'th.  This is a synonym for `1-$'.
     It is not an error to use `*' if there is just one word in the
     event; the empty string is returned in that case.

`X*'
     Abbreviates `X-$'

`X-'
     Abbreviates `X-$' like `X*', but omits the last word.

   If a word designator is supplied without an event specification, the
previous command is used as the event.


File: gdb.info,  Node: Modifiers,  Prev: Word Designators,  Up: History Interaction

Modifiers
---------

   After the optional word designator, you can add a sequence of one or
more of the following modifiers, each preceded by a `:'.

`h'
     Remove a trailing pathname component, leaving only the head.

`t'
     Remove all leading  pathname  components, leaving the tail.

`r'
     Remove a trailing suffix of the form `.SUFFIX', leaving the
     basename.

`e'
     Remove all but the trailing suffix.

`p'
     Print the new command but do not execute it.

`s/OLD/NEW/'
     Substitute NEW for the first occurrence of OLD in the event line.
     Any delimiter may be used in place of `/'.  The delimiter may be
     quoted in OLD and NEW with a single backslash.  If `&' appears in
     NEW, it is replaced by OLD.  A single backslash will quote the
     `&'.  The final delimiter is optional if it is the last character
     on the input line.

`&'
     Repeat the previous substitution.

`g'
     Cause changes to be applied over the entire event line.  Used in
     conjunction with `s', as in `gs/OLD/NEW/', or with `&'.

