rluser.texinfo

这个是LINUX下的GDB调度工具的源码

@comment %**start of header (This is for running Texinfo on a region.)
@setfilename rluser.info
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@setchapternewpage odd

@ignore
This file documents the end user interface to the GNU command line
editing features.  It is to be an appendix to manuals for programs which
use these features.  There is a document entitled "readline.texinfo"
which contains both end-user and programmer documentation for the
GNU Readline Library.

Copyright (C) 1988-2002 Free Software Foundation, Inc.

Authored by Brian Fox and Chet Ramey.

Permission is granted to process this file through Tex and print the
results, provided the printed document carries copying permission notice
identical to this one except for the removal of this paragraph (this
paragraph not being relevant to the printed manual).

Permission is granted to make and distribute verbatim copies of this manual
provided the copyright notice and this permission notice are preserved on
all copies.

Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided also that the
GNU Copyright statement is available to the distributee, and provided that
the entire resulting derived work is distributed under the terms of a
permission notice identical to this one.

Permission is granted to copy and distribute translations of this manual
into another language, under the above conditions for modified versions.
@end ignore

@comment If you are including this manual as an appendix, then set the
@comment variable readline-appendix.

@ifclear BashFeatures
@defcodeindex bt
@end ifclear

@node Command Line Editing
@chapter Command Line Editing

This chapter describes the basic features of the @sc{gnu}
command line editing interface.
@ifset BashFeatures
Command line editing is provided by the Readline library, which is
used by several different programs, including Bash.
@end ifset

@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.
@ifset BashFeatures
* Programmable Completion::	How to specify the possible completions for
				a specific command.
* Programmable Completion Builtins::	Builtin commands to specify how to
				complete arguments for a particular command.
@end ifset
@end menu

@node Introduction and Notation
@section Introduction to Line Editing

The following paragraphs describe the notation used to represent
keystrokes.

The text @kbd{C-k} is read as `Control-K' and describes the character
produced when the @key{k} key is pressed while the Control key
is depressed.

The text @kbd{M-k} is read as `Meta-K' and describes the character
produced when the Meta key (if you have one) is depressed, and the @key{k}
key is pressed.
The Meta key is labeled @key{ALT} on many keyboards.
On keyboards with two keys labeled @key{ALT} (usually to either side of
the space bar), the @key{ALT} on the left side is generally set to
work as a Meta key.
The @key{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 @key{ALT} key, or another key working as
a Meta key, the identical keystroke can be generated by typing @key{ESC}
@emph{first}, and then typing @key{k}.
Either process is known as @dfn{metafying} the @key{k} key.

The text @kbd{M-C-k} is read as `Meta-Control-k' and describes the
character produced by @dfn{metafying} @kbd{C-k}.

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

@node Readline Interaction
@section Readline Interaction
@cindex interaction, readline

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 @key{RET}.  You do not have to be at the
end of the line to press @key{RET}; 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.
@end menu

@node Readline Bare Essentials
@subsection Readline Bare Essentials
@cindex notation, readline
@cindex command editing
@cindex editing command lines

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 @kbd{C-b} to move the cursor to the left, and then
correct your mistake.  Afterwards, you can move the cursor to the right
with @kbd{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.

@table @asis
@item @kbd{C-b}
Move back one character.
@item @kbd{C-f}
Move forward one character.
@item @key{DEL} or @key{Backspace}
Delete the character to the left of the cursor.
@item @kbd{C-d}
Delete the character underneath the cursor.
@item @w{Printing characters}
Insert the character into the line at the cursor.
@item @kbd{C-_} or @kbd{C-x C-u}
Undo the last editing command.  You can undo all the way back to an
empty line.
@end table

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

@node Readline Movement Commands
@subsection 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 @kbd{C-b}, @kbd{C-f},
@kbd{C-d}, and @key{DEL}.  Here are some commands for moving more rapidly
about the line.

@table @kbd
@item C-a
Move to the start of the line.
@item C-e
Move to the end of the line.
@item M-f
Move forward a word, where a word is composed of letters and digits.
@item M-b
Move backward a word.
@item C-l
Clear the screen, reprinting the current line at the top.
@end table

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

@node Readline Killing Commands
@subsection Readline Killing Commands

@cindex killing text
@cindex yanking text

@dfn{Killing} text means to delete the text from the line, but to save
it away for later use, usually by @dfn{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 @dfn{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.
@cindex kill ring

Here is the list of commands for killing text.

@table @kbd
@item C-k
Kill the text from the current cursor position to the end of the line.

@item 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 @kbd{M-f}.

@item M-@key{DEL}
Kill from the cursor the start of the current word, or, if between
words, to the start of the previous word.
Word boundaries are the same as those used by @kbd{M-b}.

@item C-w
Kill from the cursor to the previous whitespace.  This is different than
@kbd{M-@key{DEL}} because the word boundaries differ.

@end table

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

@table @kbd
@item C-y
Yank the most recently killed text back into the buffer at the cursor.

@item M-y
Rotate the kill-ring, and yank the new top.  You can only do this if
the prior command is @kbd{C-y} or @kbd{M-y}.
@end table

@node Readline Arguments
@subsection Readline Arguments

You can pass numeric arguments to Readline commands.  Sometimes the
argument acts as a repeat count, other times it is the @i{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 @samp{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 (@samp{-}), 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 @kbd{C-d} command an argument of 10, you could type @samp{M-1 0 C-d},
which will delete the next ten characters on the input line.

@node Searching
@subsection Searching for Commands in the History

Readline provides commands for searching through the command history
@ifset BashFeatures
(@pxref{Bash History Facilities})
@end ifset
for lines containing a specified string.
There are two search modes:  @dfn{incremental} and @dfn{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
@kbd{C-r}.  Typing @kbd{C-s} searches forward through the history.
The characters present in the value of the @code{isearch-terminators} variable
are used to terminate an incremental search.
If that variable has not been assigned a value, the @key{ESC} and
@kbd{C-J} characters will terminate an incremental search.
@kbd{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 @kbd{C-r} or
@kbd{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 @key{RET} will terminate the search and accept
the line, thereby executing the command from the history list.
A movement command will terminate the search, make the last line found
the current line, and begin editing.

Readline remembers the last incremental search string.  If two
@kbd{C-r}s are typed without any intervening characters defining a new
search string, any remembered search string is used.

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.

@node Readline Init File
@section Readline Init File
@cindex initialization file, readline

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 @dfn{inputrc} file, conventionally in his home directory.
The name of this
@ifset BashFeatures
file is taken from the value of the shell variable @env{INPUTRC}.  If
@end ifset
@ifclear BashFeatures
file is taken from the value of the environment variable @env{INPUTRC}.  If
@end ifclear
that variable is unset, the default is @file{~/.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 @code{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.
@end menu

@node Readline Init File Syntax
@subsection 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 @samp{#} are comments.