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diff --git a/lib/readline/doc/rluser.texi b/lib/readline/doc/rluser.texi new file mode 100644 index 0000000..cbcbb45 --- /dev/null +++ b/lib/readline/doc/rluser.texi @@ -0,0 +1,2488 @@ +@comment %**start of header (This is for running Texinfo on a region.) +@setfilename rluser.info +@comment %**end of header (This is for running Texinfo on a region.) + +@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--2022 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. +Command line editing is enabled by default when using an interactive shell, +unless the @option{--noediting} option is supplied at shell invocation. +Line editing is also used when using the @option{-e} option to the +@code{read} builtin command (@pxref{Bash Builtins}). +By default, the line editing commands are similar to those of Emacs. +A vi-style line editing interface is also available. +Line editing can be enabled at any time using the @option{-o emacs} or +@option{-o vi} options to the @code{set} builtin command +(@pxref{The Set Builtin}), or disabled using the @option{+o emacs} or +@option{+o vi} options to @code{set}. +@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. +* A Programmable Completion Example:: An example shell function for + generating possible completions. +@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 might 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 to 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 their 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}. If that +file does not exist or cannot be read, the ultimate default is +@file{/etc/inputrc}. +@ifset BashFeatures +The @w{@code{bind}} builtin command can also be used to set Readline +keybindings and variables. +@xref{Bash Builtins}. +@end ifset + +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. +Lines beginning with a @samp{$} indicate conditional +constructs (@pxref{Conditional Init Constructs}). Other lines +denote variable settings and key bindings. + +@table @asis +@item Variable Settings +You can modify the run-time behavior of Readline by +altering the values of variables in Readline +using the @code{set} command within the init file. +The syntax is simple: + +@example +set @var{variable} @var{value} +@end example + +@noindent +Here, for example, is how to +change from the default Emacs-like key binding to use +@code{vi} line editing commands: + +@example +set editing-mode vi +@end example + +Variable names and values, where appropriate, are recognized without regard +to case. Unrecognized variable names are ignored. + +Boolean variables (those that can be set to on or off) are set to on if +the value is null or empty, @var{on} (case-insensitive), or 1. Any other +value results in the variable being set to off. + +@ifset BashFeatures +The @w{@code{bind -V}} command lists the current Readline variable names +and values. @xref{Bash Builtins}. +@end ifset + +A great deal of run-time behavior is changeable with the following +variables. + +@cindex variables, readline +@table @code + +@item active-region-start-color +@vindex active-region-start-color +A string variable that controls the text color and background when displaying +the text in the active region (see the description of +@code{enable-active-region} below). +This string must not take up any physical character positions on the display, +so it should consist only of terminal escape sequences. +It is output to the terminal before displaying the text in the active region. +This variable is reset to the default value whenever the terminal type changes. +The default value is the string that puts the terminal in standout mode, +as obtained from the terminal's terminfo description. +A sample value might be @samp{\e[01;33m}. + +@item active-region-end-color +@vindex active-region-end-color +A string variable that "undoes" the effects of @code{active-region-start-color} +and restores "normal" terminal display appearance after displaying text +in the active region. +This string must not take up any physical character positions on the display, +so it should consist only of terminal escape sequences. +It is output to the terminal after displaying the text in the active region. +This variable is reset to the default value whenever the terminal type changes. +The default value is the string that restores the terminal from standout mode, +as obtained from the terminal's terminfo description. +A sample value might be @samp{\e[0m}. + +@item bell-style +@vindex bell-style +Controls what happens when Readline wants to ring the terminal bell. +If set to @samp{none}, Readline never rings the bell. If set to +@samp{visible}, Readline uses a visible bell if one is available. +If set to @samp{audible} (the default), Readline attempts to ring +the terminal's bell. + +@item bind-tty-special-chars +@vindex bind-tty-special-chars +If set to @samp{on} (the default), Readline attempts to bind the control +characters treated specially by the kernel's terminal driver to their +Readline equivalents. + +@item blink-matching-paren +@vindex blink-matching-paren +If set to @samp{on}, Readline attempts to briefly move the cursor to an +opening parenthesis when a closing parenthesis is inserted. The default +is @samp{off}. + +@item colored-completion-prefix +@vindex colored-completion-prefix +If set to @samp{on}, when listing completions, Readline displays the +common prefix of the set of possible completions using a different color. +The color definitions are taken from the value of the @env{LS_COLORS} +environment variable. +If there is a color definition in @env{LS_COLORS} for the custom suffix +@samp{readline-colored-completion-prefix}, Readline uses this color for +the common prefix instead of its default. +The default is @samp{off}. + +@item colored-stats +@vindex colored-stats +If set to @samp{on}, Readline displays possible completions using different +colors to indicate their file type. +The color definitions are taken from the value of the @env{LS_COLORS} +environment variable. +The default is @samp{off}. + +@item comment-begin +@vindex comment-begin +The string to insert at the beginning of the line when the +@code{insert-comment} command is executed. The default value +is @code{"#"}. + +@item completion-display-width +@vindex completion-display-width +The number of screen columns used to display possible matches +when performing completion. +The value is ignored if it is less than 0 or greater than the terminal +screen width. +A value of 0 will cause matches to be displayed one per line. +The default value is -1. + +@item completion-ignore-case +@vindex completion-ignore-case +If set to @samp{on}, Readline performs filename matching and completion +in a case-insensitive fashion. +The default value is @samp{off}. + +@item completion-map-case +@vindex completion-map-case +If set to @samp{on}, and @var{completion-ignore-case} is enabled, Readline +treats hyphens (@samp{-}) and underscores (@samp{_}) as equivalent when +performing case-insensitive filename matching and completion. +The default value is @samp{off}. + +@item completion-prefix-display-length +@vindex completion-prefix-display-length +The length in characters of the common prefix of a list of possible +completions that is displayed without modification. When set to a +value greater than zero, common prefixes longer than this value are +replaced with an ellipsis when displaying possible completions. + +@item completion-query-items +@vindex completion-query-items +The number of possible completions that determines when the user is +asked whether the list of possibilities should be displayed. +If the number of possible completions is greater than or equal to this value, +Readline will ask whether or not the user wishes to view them; +otherwise, they are simply listed. +This variable must be set to an integer value greater than or equal to zero. +A zero value means Readline should never ask; negative values are +treated as zero. +The default limit is @code{100}. + +@item convert-meta +@vindex convert-meta +If set to @samp{on}, Readline will convert characters with the +eighth bit set to an @sc{ascii} key sequence by stripping the eighth +bit and prefixing an @key{ESC} character, converting them to a +meta-prefixed key sequence. +The default value is @samp{on}, but +will be set to @samp{off} if the locale is one that contains +eight-bit characters. +This variable is dependent on the @code{LC_CTYPE} locale category, and +may change if the locale is changed. + +@item disable-completion +@vindex disable-completion +If set to @samp{On}, Readline will inhibit word completion. +Completion characters will be inserted into the line as if they had +been mapped to @code{self-insert}. The default is @samp{off}. + +@item echo-control-characters +@vindex echo-control-characters +When set to @samp{on}, on operating systems that indicate they support it, +Readline echoes a character corresponding to a signal generated from the +keyboard. The default is @samp{on}. + +@item editing-mode +@vindex editing-mode +The @code{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 @samp{emacs} or @samp{vi}. + +@item emacs-mode-string +@vindex emacs-mode-string +If the @var{show-mode-in-prompt} variable is enabled, +this string is displayed immediately before the last line of the primary +prompt when emacs editing mode is active. The value is expanded like a +key binding, so the standard set of meta- and control prefixes and +backslash escape sequences is available. +Use the @samp{\1} and @samp{\2} escapes to begin and end sequences of +non-printing characters, which can be used to embed a terminal control +sequence into the mode string. +The default is @samp{@@}. + +@item enable-active-region +@vindex enable-active-region +The @dfn{point} is the current cursor position, and @dfn{mark} refers +to a saved cursor position (@pxref{Commands For Moving}). +The text between the point and mark is referred to as the @dfn{region}. +When this variable is set to @samp{On}, Readline allows certain commands +to designate the region as @dfn{active}. +When the region is active, Readline highlights the text in the region using +the value of the @code{active-region-start-color}, which defaults to the +string that enables +the terminal's standout mode. +The active region shows the text inserted by bracketed-paste and any +matching text found by incremental and non-incremental history searches. +The default is @samp{On}. + +@item enable-bracketed-paste +@vindex enable-bracketed-paste +When set to @samp{On}, Readline configures the terminal to insert each +paste into the editing buffer as a single string of characters, instead +of treating each character as if it had been read from the keyboard. +This is called putting the terminal into @dfn{bracketed paste mode}; +it prevents Readline from executing any editing commands bound to key +sequences appearing in the pasted text. +The default is @samp{On}. + +@item enable-keypad +@vindex enable-keypad +When set to @samp{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 @samp{off}. + +@item enable-meta-key +When set to @samp{on}, Readline will try to enable any meta modifier +key the terminal claims to support when it is called. On many terminals, +the meta key is used to send eight-bit characters. +The default is @samp{on}. + +@item expand-tilde +@vindex expand-tilde +If set to @samp{on}, tilde expansion is performed when Readline +attempts word completion. The default is @samp{off}. + +@item history-preserve-point +@vindex history-preserve-point +If set to @samp{on}, the history code attempts to place the point (the +current cursor position) at the +same location on each history line retrieved with @code{previous-history} +or @code{next-history}. The default is @samp{off}. + +@item history-size +@vindex history-size +Set the maximum number of history entries saved in the history list. +If set to zero, any existing history entries are deleted and no new entries +are saved. +If set to a value less than zero, the number of history entries is not +limited. +By default, the number of history entries is not limited. +If an attempt is made to set @var{history-size} to a non-numeric value, +the maximum number of history entries will be set to 500. + +@item horizontal-scroll-mode +@vindex horizontal-scroll-mode +This variable can be set to either @samp{on} or @samp{off}. Setting it +to @samp{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. +This variable is automatically set to @samp{on} for terminals of height 1. +By default, this variable is set to @samp{off}. + +@item input-meta +@vindex input-meta +@vindex meta-flag +If set to @samp{on}, Readline will enable eight-bit input (it +will not clear the eighth bit in the characters it reads), +regardless of what the terminal claims it can support. The +default value is @samp{off}, but Readline will set it to @samp{on} if the +locale contains eight-bit characters. +The name @code{meta-flag} is a synonym for this variable. +This variable is dependent on the @code{LC_CTYPE} locale category, and +may change if the locale is changed. + +@item isearch-terminators +@vindex isearch-terminators +The string of characters that should terminate an incremental search without +subsequently executing the character as a command (@pxref{Searching}). +If this variable has not been given a value, the characters @key{ESC} and +@kbd{C-J} will terminate an incremental search. + +@item keymap +@vindex keymap +Sets Readline's idea of the current keymap for key binding commands. +Built-in @code{keymap} names are +@code{emacs}, +@code{emacs-standard}, +@code{emacs-meta}, +@code{emacs-ctlx}, +@code{vi}, +@code{vi-move}, +@code{vi-command}, and +@code{vi-insert}. +@code{vi} is equivalent to @code{vi-command} (@code{vi-move} is also a +synonym); @code{emacs} is equivalent to @code{emacs-standard}. +Applications may add additional names. +The default value is @code{emacs}. +The value of the @code{editing-mode} variable also affects the +default keymap. + +@item keyseq-timeout +Specifies the duration Readline will wait for a character when reading an +ambiguous key sequence (one that can form a complete key sequence using +the input read so far, or can take additional input to complete a longer +key sequence). +If no input is received within the timeout, Readline will use the shorter +but complete key sequence. +Readline uses this value to determine whether or not input is +available on the current input source (@code{rl_instream} by default). +The value is specified in milliseconds, so a value of 1000 means that +Readline will wait one second for additional input. +If this variable is set to a value less than or equal to zero, or to a +non-numeric value, Readline will wait until another key is pressed to +decide which key sequence to complete. +The default value is @code{500}. + +@item mark-directories +If set to @samp{on}, completed directory names have a slash +appended. The default is @samp{on}. + +@item mark-modified-lines +@vindex mark-modified-lines +This variable, when set to @samp{on}, causes Readline to display an +asterisk (@samp{*}) at the start of history lines which have been modified. +This variable is @samp{off} by default. + +@item mark-symlinked-directories +@vindex mark-symlinked-directories +If set to @samp{on}, completed names which are symbolic links +to directories have a slash appended (subject to the value of +@code{mark-directories}). +The default is @samp{off}. + +@item match-hidden-files +@vindex match-hidden-files +This variable, when set to @samp{on}, causes Readline to match files whose +names begin with a @samp{.} (hidden files) when performing filename +completion. +If set to @samp{off}, the leading @samp{.} must be +supplied by the user in the filename to be completed. +This variable is @samp{on} by default. + +@item menu-complete-display-prefix +@vindex menu-complete-display-prefix +If set to @samp{on}, menu completion displays the common prefix of the +list of possible completions (which may be empty) before cycling through +the list. The default is @samp{off}. + +@item output-meta +@vindex output-meta +If set to @samp{on}, Readline will display characters with the +eighth bit set directly rather than as a meta-prefixed escape +sequence. +The default is @samp{off}, but Readline will set it to @samp{on} if the +locale contains eight-bit characters. +This variable is dependent on the @code{LC_CTYPE} locale category, and +may change if the locale is changed. + +@item page-completions +@vindex page-completions +If set to @samp{on}, Readline uses an internal @code{more}-like pager +to display a screenful of possible completions at a time. +This variable is @samp{on} by default. + +@item print-completions-horizontally +If set to @samp{on}, Readline will display completions with matches +sorted horizontally in alphabetical order, rather than down the screen. +The default is @samp{off}. + +@item revert-all-at-newline +@vindex revert-all-at-newline +If set to @samp{on}, Readline will undo all changes to history lines +before returning when @code{accept-line} is executed. By default, +history lines may be modified and retain individual undo lists across +calls to @code{readline()}. The default is @samp{off}. + +@item show-all-if-ambiguous +@vindex show-all-if-ambiguous +This alters the default behavior of the completion functions. If +set to @samp{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 @samp{off}. + +@item show-all-if-unmodified +@vindex show-all-if-unmodified +This alters the default behavior of the completion functions in +a fashion similar to @var{show-all-if-ambiguous}. +If set to @samp{on}, +words which have more than one possible completion without any +possible partial completion (the possible completions don't share +a common prefix) cause the matches to be listed immediately instead +of ringing the bell. +The default value is @samp{off}. + +@item show-mode-in-prompt +@vindex show-mode-in-prompt +If set to @samp{on}, add a string to the beginning of the prompt +indicating the editing mode: emacs, vi command, or vi insertion. +The mode strings are user-settable (e.g., @var{emacs-mode-string}). +The default value is @samp{off}. + +@item skip-completed-text +@vindex skip-completed-text +If set to @samp{on}, this alters the default completion behavior when +inserting a single match into the line. It's only active when +performing completion in the middle of a word. If enabled, Readline +does not insert characters from the completion that match characters +after point in the word being completed, so portions of the word +following the cursor are not duplicated. +For instance, if this is enabled, attempting completion when the cursor +is after the @samp{e} in @samp{Makefile} will result in @samp{Makefile} +rather than @samp{Makefilefile}, assuming there is a single possible +completion. +The default value is @samp{off}. + +@item vi-cmd-mode-string +@vindex vi-cmd-mode-string +If the @var{show-mode-in-prompt} variable is enabled, +this string is displayed immediately before the last line of the primary +prompt when vi editing mode is active and in command mode. +The value is expanded like a +key binding, so the standard set of meta- and control prefixes and +backslash escape sequences is available. +Use the @samp{\1} and @samp{\2} escapes to begin and end sequences of +non-printing characters, which can be used to embed a terminal control +sequence into the mode string. +The default is @samp{(cmd)}. + +@item vi-ins-mode-string +@vindex vi-ins-mode-string +If the @var{show-mode-in-prompt} variable is enabled, +this string is displayed immediately before the last line of the primary +prompt when vi editing mode is active and in insertion mode. +The value is expanded like a +key binding, so the standard set of meta- and control prefixes and +backslash escape sequences is available. +Use the @samp{\1} and @samp{\2} escapes to begin and end sequences of +non-printing characters, which can be used to embed a terminal control +sequence into the mode string. +The default is @samp{(ins)}. + +@item visible-stats +@vindex visible-stats +If set to @samp{on}, a character denoting a file's type +is appended to the filename when listing possible +completions. The default is @samp{off}. + +@end table + +@item 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 on a line +in the init file the name of the key +you wish to bind the command to, a colon, and then the name of the +command. +There can be no space between the key name and the colon -- that will be +interpreted as part of the key name. +The name of the key can be expressed in different ways, depending on +what you find most comfortable. + +In addition to command names, Readline allows keys to be bound +to a string that is inserted when the key is pressed (a @var{macro}). + +@ifset BashFeatures +The @w{@code{bind -p}} command displays Readline function names and +bindings in a format that can be put directly into an initialization file. +@xref{Bash Builtins}. +@end ifset + +@table @asis +@item @w{@var{keyname}: @var{function-name} or @var{macro}} +@var{keyname} is the name of a key spelled out in English. For example: +@example +Control-u: universal-argument +Meta-Rubout: backward-kill-word +Control-o: "> output" +@end example + +In the example above, @kbd{C-u} is bound to the function +@code{universal-argument}, +@kbd{M-DEL} is bound to the function @code{backward-kill-word}, and +@kbd{C-o} is bound to run the macro +expressed on the right hand side (that is, to insert the text +@samp{> output} into the line). + +A number of symbolic character names are recognized while +processing this key binding syntax: +@var{DEL}, +@var{ESC}, +@var{ESCAPE}, +@var{LFD}, +@var{NEWLINE}, +@var{RET}, +@var{RETURN}, +@var{RUBOUT}, +@var{SPACE}, +@var{SPC}, +and +@var{TAB}. + +@item @w{"@var{keyseq}": @var{function-name} or @var{macro}} +@var{keyseq} differs from @var{keyname} above in that strings +denoting an entire key sequence can be specified, by placing +the key sequence in double quotes. Some @sc{gnu} Emacs style key +escapes can be used, as in the following example, but the +special character names are not recognized. + +@example +"\C-u": universal-argument +"\C-x\C-r": re-read-init-file +"\e[11~": "Function Key 1" +@end example + +In the above example, @kbd{C-u} is again bound to the function +@code{universal-argument} (just as it was in the first example), +@samp{@kbd{C-x} @kbd{C-r}} is bound to the function @code{re-read-init-file}, +and @samp{@key{ESC} @key{[} @key{1} @key{1} @key{~}} is bound to insert +the text @samp{Function Key 1}. + +@end table + +The following @sc{gnu} Emacs style escape sequences are available when +specifying key sequences: + +@table @code +@item @kbd{\C-} +control prefix +@item @kbd{\M-} +meta prefix +@item @kbd{\e} +an escape character +@item @kbd{\\} +backslash +@item @kbd{\"} +@key{"}, a double quotation mark +@item @kbd{\'} +@key{'}, a single quote or apostrophe +@end table + +In addition to the @sc{gnu} Emacs style escape sequences, a second +set of backslash escapes is available: + +@table @code +@item \a +alert (bell) +@item \b +backspace +@item \d +delete +@item \f +form feed +@item \n +newline +@item \r +carriage return +@item \t +horizontal tab +@item \v +vertical tab +@item \@var{nnn} +the eight-bit character whose value is the octal value @var{nnn} +(one to three digits) +@item \x@var{HH} +the eight-bit character whose value is the hexadecimal value @var{HH} +(one or two hex digits) +@end table + +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 @samp{"} and @samp{'}. +For example, the following binding will make @samp{@kbd{C-x} \} +insert a single @samp{\} into the line: +@example +"\C-x\\": "\\" +@end example + +@end table + +@node Conditional Init Constructs +@subsection 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. + +@table @code +@item $if +The @code{$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, after any comparison operator, +extends to the end of the line; +unless otherwise noted, no characters are required to isolate it. + +@table @code +@item mode +The @code{mode=} form of the @code{$if} directive is used to test +whether Readline is in @code{emacs} or @code{vi} mode. +This may be used in conjunction +with the @samp{set keymap} command, for instance, to set bindings in +the @code{emacs-standard} and @code{emacs-ctlx} keymaps only if +Readline is starting out in @code{emacs} mode. + +@item term +The @code{term=} form may be used to include terminal-specific +key bindings, perhaps to bind the key sequences output by the +terminal's function keys. The word on the right side of the +@samp{=} is tested against both the full name of the terminal and +the portion of the terminal name before the first @samp{-}. This +allows @code{sun} to match both @code{sun} and @code{sun-cmd}, +for instance. + +@item version +The @code{version} test may be used to perform comparisons against +specific Readline versions. +The @code{version} expands to the current Readline version. +The set of comparison operators includes +@samp{=} (and @samp{==}), @samp{!=}, @samp{<=}, @samp{>=}, @samp{<}, +and @samp{>}. +The version number supplied on the right side of the operator consists +of a major version number, an optional decimal point, and an optional +minor version (e.g., @samp{7.1}). If the minor version is omitted, it +is assumed to be @samp{0}. +The operator may be separated from the string @code{version} and +from the version number argument by whitespace. +The following example sets a variable if the Readline version being used +is 7.0 or newer: +@example +$if version >= 7.0 +set show-mode-in-prompt on +$endif +@end example + +@item application +The @var{application} construct is used to include +application-specific settings. Each program using the Readline +library sets the @var{application name}, and you can test for +a particular value. +This could be used to bind key sequences to functions useful for +a specific program. For instance, the following command adds a +key sequence that quotes the current or previous word in Bash: +@example +$if Bash +# Quote the current or previous word +"\C-xq": "\eb\"\ef\"" +$endif +@end example + +@item variable +The @var{variable} construct provides simple equality tests for Readline +variables and values. +The permitted comparison operators are @samp{=}, @samp{==}, and @samp{!=}. +The variable name must be separated from the comparison operator by +whitespace; the operator may be separated from the value on the right hand +side by whitespace. +Both string and boolean variables may be tested. Boolean variables must be +tested against the values @var{on} and @var{off}. +The following example is equivalent to the @code{mode=emacs} test described +above: +@example +$if editing-mode == emacs +set show-mode-in-prompt on +$endif +@end example +@end table + +@item $endif +This command, as seen in the previous example, terminates an +@code{$if} command. + +@item $else +Commands in this branch of the @code{$if} directive are executed if +the test fails. + +@item $include +This directive takes a single filename as an argument and reads commands +and bindings from that file. +For example, the following directive reads from @file{/etc/inputrc}: +@example +$include /etc/inputrc +@end example +@end table + +@node Sample Init File +@subsection Sample Init File + +Here is an example of an @var{inputrc} file. This illustrates key +binding, variable assignment, and conditional syntax. + +@example +@page +# 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 system-wide 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=" +$endif + +# use a visible bell if one is available +set bell-style visible + +# don't strip characters to 7 bits when reading +set input-meta on + +# allow iso-latin1 characters to be inserted rather +# than converted to prefix-meta sequences +set convert-meta off + +# display characters with the eighth bit set directly +# rather than as meta-prefixed characters +set output-meta on + +# if there are 150 or more possible completions for a word, +# ask whether or not the user wants to see all of them +set completion-query-items 150 + +# For FTP +$if Ftp +"\C-xg": "get \M-?" +"\C-xt": "put \M-?" +"\M-.": yank-last-arg +$endif +@end example + +@node Bindable Readline Commands +@section 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. +@end menu + +This section describes Readline commands that may be bound to key +sequences. +@ifset BashFeatures +You can list your key bindings by executing +@w{@code{bind -P}} or, for a more terse format, suitable for an +@var{inputrc} file, @w{@code{bind -p}}. (@xref{Bash Builtins}.) +@end ifset +Command names without an accompanying key sequence are unbound by default. + +In the following descriptions, @dfn{point} refers to the current cursor +position, and @dfn{mark} refers to a cursor position saved by the +@code{set-mark} command. +The text between the point and mark is referred to as the @dfn{region}. + +@node Commands For Moving +@subsection Commands For Moving +@ftable @code +@item beginning-of-line (C-a) +Move to the start of the current line. + +@item end-of-line (C-e) +Move to the end of the line. + +@item forward-char (C-f) +Move forward a character. + +@item backward-char (C-b) +Move back a character. + +@item forward-word (M-f) +Move forward to the end of the next word. +Words are composed of letters and digits. + +@item backward-word (M-b) +Move back to the start of the current or previous word. +Words are composed of letters and digits. + +@ifset BashFeatures +@item shell-forward-word (M-C-f) +Move forward to the end of the next word. +Words are delimited by non-quoted shell metacharacters. + +@item shell-backward-word (M-C-b) +Move back to the start of the current or previous word. +Words are delimited by non-quoted shell metacharacters. +@end ifset + +@item previous-screen-line () +Attempt to move point to the same physical screen column on the previous +physical screen line. This will not have the desired effect if the current +Readline line does not take up more than one physical line or if point is not +greater than the length of the prompt plus the screen width. + +@item next-screen-line () +Attempt to move point to the same physical screen column on the next +physical screen line. This will not have the desired effect if the current +Readline line does not take up more than one physical line or if the length +of the current Readline line is not greater than the length of the prompt +plus the screen width. + +@item clear-display (M-C-l) +Clear the screen and, if possible, the terminal's scrollback buffer, +then redraw the current line, +leaving the current line at the top of the screen. + +@item clear-screen (C-l) +Clear the screen, +then redraw the current line, +leaving the current line at the top of the screen. + +@item redraw-current-line () +Refresh the current line. By default, this is unbound. + +@end ftable + +@node Commands For History +@subsection Commands For Manipulating The History + +@ftable @code +@item accept-line (Newline or Return) +@ifset BashFeatures +Accept the line regardless of where the cursor is. +If this line is +non-empty, add it to the history list according to the setting of +the @env{HISTCONTROL} and @env{HISTIGNORE} variables. +If this line is a modified history line, then restore the history line +to its original state. +@end ifset +@ifclear BashFeatures +Accept the line regardless of where the cursor is. +If this line is +non-empty, it may be added to the history list for future recall with +@code{add_history()}. +If this line is a modified history line, the history line is restored +to its original state. +@end ifclear + +@item previous-history (C-p) +Move `back' through the history list, fetching the previous command. + +@item next-history (C-n) +Move `forward' through the history list, fetching the next command. + +@item beginning-of-history (M-<) +Move to the first line in the history. + +@item end-of-history (M->) +Move to the end of the input history, i.e., the line currently +being entered. + +@item 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. +This command sets the region to the matched text and activates the mark. + +@item forward-search-history (C-s) +Search forward starting at the current line and moving `down' through +the history as necessary. This is an incremental search. +This command sets the region to the matched text and activates the mark. + +@item 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. +The search string may match anywhere in a history line. + +@item non-incremental-forward-search-history (M-n) +Search forward starting at the current line and moving `down' +through the history as necessary using a non-incremental search +for a string supplied by the user. +The search string may match anywhere in a history line. + +@item history-search-forward () +Search forward through the history for the string of characters +between the start of the current line and the point. +The search string must match at the beginning of a history line. +This is a non-incremental search. +By default, this command is unbound. + +@item history-search-backward () +Search backward through the history for the string of characters +between the start of the current line and the point. +The search string must match at the beginning of a history line. +This is a non-incremental search. +By default, this command is unbound. + +@item history-substring-search-forward () +Search forward through the history for the string of characters +between the start of the current line and the point. +The search string may match anywhere in a history line. +This is a non-incremental search. +By default, this command is unbound. + +@item history-substring-search-backward () +Search backward through the history for the string of characters +between the start of the current line and the point. +The search string may match anywhere in a history line. +This is a non-incremental search. +By default, this command is unbound. + +@item yank-nth-arg (M-C-y) +Insert the first argument to the previous command (usually +the second word on the previous line) at point. +With an argument @var{n}, +insert the @var{n}th word from the previous command (the words +in the previous command begin with word 0). A negative argument +inserts the @var{n}th word from the end of the previous command. +Once the argument @var{n} is computed, the argument is extracted +as if the @samp{!@var{n}} history expansion had been specified. + +@item yank-last-arg (M-. or M-_) +Insert last argument to the previous command (the last word of the +previous history entry). +With a numeric argument, behave exactly like @code{yank-nth-arg}. +Successive calls to @code{yank-last-arg} move back through the history +list, inserting the last word (or the word specified by the argument to +the first call) of each line in turn. +Any numeric argument supplied to these successive calls determines +the direction to move through the history. A negative argument switches +the direction through the history (back or forward). +The history expansion facilities are used to extract the last argument, +as if the @samp{!$} history expansion had been specified. + +@item operate-and-get-next (C-o) +Accept the current line for return to the calling application as if a +newline had been entered, +and fetch the next line relative to the current line from the history +for editing. +A numeric argument, if supplied, specifies the history entry to use instead +of the current line. + +@item fetch-history () +With a numeric argument, fetch that entry from the history list +and make it the current line. +Without an argument, move back to the first entry in the history list. + +@end ftable + +@node Commands For Text +@subsection Commands For Changing Text + +@ftable @code + +@item @i{end-of-file} (usually C-d) +The character indicating end-of-file as set, for example, by +@code{stty}. If this character is read when there are no characters +on the line, and point is at the beginning of the line, Readline +interprets it as the end of input and returns @sc{eof}. + +@item delete-char (C-d) +Delete the character at point. If this function is bound to the +same character as the tty @sc{eof} character, as @kbd{C-d} +commonly is, see above for the effects. + +@item backward-delete-char (Rubout) +Delete the character behind the cursor. A numeric argument means +to kill the characters instead of deleting them. + +@item 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. + +@item quoted-insert (C-q or C-v) +Add the next character typed to the line verbatim. This is +how to insert key sequences like @kbd{C-q}, for example. + +@ifclear BashFeatures +@item tab-insert (M-@key{TAB}) +Insert a tab character. +@end ifclear + +@item self-insert (a, b, A, 1, !, @dots{}) +Insert yourself. + +@item bracketed-paste-begin () +This function is intended to be bound to the "bracketed paste" escape +sequence sent by some terminals, and such a binding is assigned by default. +It allows Readline to insert the pasted text as a single unit without treating +each character as if it had been read from the keyboard. The characters +are inserted as if each one was bound to @code{self-insert} instead of +executing any editing commands. + +Bracketed paste sets the region (the characters between point and the mark) +to the inserted text. It uses the concept of an @emph{active mark}: when the +mark is active, Readline redisplay uses the terminal's standout mode to +denote the region. + +@item 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. + +@item transpose-words (M-t) +Drag the word before point past the word after point, +moving point past that word as well. +If the insertion point is at the end of the line, this transposes +the last two words on the line. + +@item upcase-word (M-u) +Uppercase the current (or following) word. With a negative argument, +uppercase the previous word, but do not move the cursor. + +@item downcase-word (M-l) +Lowercase the current (or following) word. With a negative argument, +lowercase the previous word, but do not move the cursor. + +@item capitalize-word (M-c) +Capitalize the current (or following) word. With a negative argument, +capitalize the previous word, but do not move the cursor. + +@item overwrite-mode () +Toggle overwrite mode. With an explicit positive numeric argument, +switches to overwrite mode. With an explicit non-positive numeric +argument, switches to insert mode. This command affects only +@code{emacs} mode; @code{vi} mode does overwrite differently. +Each call to @code{readline()} starts in insert mode. + +In overwrite mode, characters bound to @code{self-insert} replace +the text at point rather than pushing the text to the right. +Characters bound to @code{backward-delete-char} replace the character +before point with a space. + +By default, this command is unbound. + +@end ftable + +@node Commands For Killing +@subsection Killing And Yanking + +@ftable @code + +@item kill-line (C-k) +Kill the text from point to the end of the line. +With a negative numeric argument, kill backward from the cursor to the +beginning of the current line. + +@item backward-kill-line (C-x Rubout) +Kill backward from the cursor to the beginning of the current line. +With a negative numeric argument, kill forward from the cursor to the +end of the current line. + +@item unix-line-discard (C-u) +Kill backward from the cursor to the beginning of the current line. + +@item kill-whole-line () +Kill all characters on the current line, no matter where point is. +By default, this is unbound. + +@item 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 @code{forward-word}. + +@item backward-kill-word (M-@key{DEL}) +Kill the word behind point. +Word boundaries are the same as @code{backward-word}. + +@ifset BashFeatures +@item shell-kill-word (M-C-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 @code{shell-forward-word}. + +@item shell-backward-kill-word () +Kill the word behind point. +Word boundaries are the same as @code{shell-backward-word}. +@end ifset + +@item shell-transpose-words (M-C-t) +Drag the word before point past the word after point, +moving point past that word as well. +If the insertion point is at the end of the line, this transposes +the last two words on the line. +Word boundaries are the same as @code{shell-forward-word} and +@code{shell-backward-word}. + +@item 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. + +@item unix-filename-rubout () +Kill the word behind point, using white space and the slash character +as the word boundaries. +The killed text is saved on the kill-ring. + +@item delete-horizontal-space () +Delete all spaces and tabs around point. By default, this is unbound. + +@item kill-region () +Kill the text in the current region. +By default, this command is unbound. + +@item 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. + +@item copy-backward-word () +Copy the word before point to the kill buffer. +The word boundaries are the same as @code{backward-word}. +By default, this command is unbound. + +@item copy-forward-word () +Copy the word following point to the kill buffer. +The word boundaries are the same as @code{forward-word}. +By default, this command is unbound. + +@item yank (C-y) +Yank the top of the kill ring into the buffer at point. + +@item yank-pop (M-y) +Rotate the kill-ring, and yank the new top. You can only do this if +the prior command is @code{yank} or @code{yank-pop}. +@end ftable + +@node Numeric Arguments +@subsection Specifying Numeric Arguments +@ftable @code + +@item digit-argument (@kbd{M-0}, @kbd{M-1}, @dots{} @kbd{M--}) +Add this digit to the argument already accumulating, or start a new +argument. @kbd{M--} starts a negative argument. + +@item 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 @code{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 nor 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. +@end ftable + +@node Commands For Completion +@subsection Letting Readline Type For You + +@ftable @code +@item complete (@key{TAB}) +Attempt to perform completion on the text before point. +The actual completion performed is application-specific. +@ifset BashFeatures +Bash attempts completion treating the text as a variable (if the +text begins with @samp{$}), username (if the text begins with +@samp{~}), hostname (if the text begins with @samp{@@}), or +command (including aliases and functions) in turn. If none +of these produces a match, filename completion is attempted. +@end ifset +@ifclear BashFeatures +The default is filename completion. +@end ifclear + +@item possible-completions (M-?) +List the possible completions of the text before point. +When displaying completions, Readline sets the number of columns used +for display to the value of @code{completion-display-width}, the value of +the environment variable @env{COLUMNS}, or the screen width, in that order. + +@item insert-completions (M-*) +Insert all completions of the text before point that would have +been generated by @code{possible-completions}. + +@item menu-complete () +Similar to @code{complete}, but replaces the word to be completed +with a single match from the list of possible completions. +Repeated execution of @code{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 +(subject to the setting of @code{bell-style}) +and the original text is restored. +An argument of @var{n} moves @var{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 @key{TAB}, but is unbound +by default. + +@item menu-complete-backward () +Identical to @code{menu-complete}, but moves backward through the list +of possible completions, as if @code{menu-complete} had been given a +negative argument. + +@item delete-char-or-list () +Deletes the character under the cursor if not at the beginning or +end of the line (like @code{delete-char}). +If at the end of the line, behaves identically to +@code{possible-completions}. +This command is unbound by default. + +@ifset BashFeatures +@item complete-filename (M-/) +Attempt filename completion on the text before point. + +@item possible-filename-completions (C-x /) +List the possible completions of the text before point, +treating it as a filename. + +@item complete-username (M-~) +Attempt completion on the text before point, treating +it as a username. + +@item possible-username-completions (C-x ~) +List the possible completions of the text before point, +treating it as a username. + +@item complete-variable (M-$) +Attempt completion on the text before point, treating +it as a shell variable. + +@item possible-variable-completions (C-x $) +List the possible completions of the text before point, +treating it as a shell variable. + +@item complete-hostname (M-@@) +Attempt completion on the text before point, treating +it as a hostname. + +@item possible-hostname-completions (C-x @@) +List the possible completions of the text before point, +treating it as a hostname. + +@item complete-command (M-!) +Attempt completion on the text before point, treating +it as a command name. Command completion attempts to +match the text against aliases, reserved words, shell +functions, shell builtins, and finally executable filenames, +in that order. + +@item possible-command-completions (C-x !) +List the possible completions of the text before point, +treating it as a command name. + +@item dynamic-complete-history (M-@key{TAB}) +Attempt completion on the text before point, comparing +the text against lines from the history list for possible +completion matches. + +@item dabbrev-expand () +Attempt menu completion on the text before point, comparing +the text against lines from the history list for possible +completion matches. + +@item complete-into-braces (M-@{) +Perform filename completion and insert the list of possible completions +enclosed within braces so the list is available to the shell +(@pxref{Brace Expansion}). + +@end ifset +@end ftable + +@node Keyboard Macros +@subsection Keyboard Macros +@ftable @code + +@item start-kbd-macro (C-x () +Begin saving the characters typed into the current keyboard macro. + +@item end-kbd-macro (C-x )) +Stop saving the characters typed into the current keyboard macro +and save the definition. + +@item 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. + +@item print-last-kbd-macro () +Print the last keyboard macro defined in a format suitable for the +@var{inputrc} file. + +@end ftable + +@node Miscellaneous Commands +@subsection Some Miscellaneous Commands +@ftable @code + +@item re-read-init-file (C-x C-r) +Read in the contents of the @var{inputrc} file, and incorporate +any bindings or variable assignments found there. + +@item abort (C-g) +Abort the current editing command and +ring the terminal's bell (subject to the setting of +@code{bell-style}). + +@item do-lowercase-version (M-A, M-B, M-@var{x}, @dots{}) +If the metafied character @var{x} is upper case, run the command +that is bound to the corresponding metafied lower case character. +The behavior is undefined if @var{x} is already lower case. + +@item prefix-meta (@key{ESC}) +Metafy the next character typed. This is for keyboards +without a meta key. Typing @samp{@key{ESC} f} is equivalent to typing +@kbd{M-f}. + +@item undo (C-_ or C-x C-u) +Incremental undo, separately remembered for each line. + +@item revert-line (M-r) +Undo all changes made to this line. This is like executing the @code{undo} +command enough times to get back to the beginning. + +@ifset BashFeatures +@item tilde-expand (M-&) +@end ifset +@ifclear BashFeatures +@item tilde-expand (M-~) +@end ifclear +Perform tilde expansion on the current word. + +@item set-mark (C-@@) +Set the mark to the point. If a +numeric argument is supplied, the mark is set to that position. + +@item 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. + +@item character-search (C-]) +A character is read and point is moved to the next occurrence of that +character. A negative argument searches for previous occurrences. + +@item character-search-backward (M-C-]) +A character is read and point is moved to the previous occurrence +of that character. A negative argument searches for subsequent +occurrences. + +@item skip-csi-sequence () +Read enough characters to consume a multi-key sequence such as those +defined for keys like Home and End. Such sequences begin with a +Control Sequence Indicator (CSI), usually ESC-[. If this sequence is +bound to "\e[", keys producing such sequences will have no effect +unless explicitly bound to a Readline command, instead of inserting +stray characters into the editing buffer. This is unbound by default, +but usually bound to ESC-[. + +@item insert-comment (M-#) +Without a numeric argument, the value of the @code{comment-begin} +variable is inserted at the beginning of the current line. +If a numeric argument is supplied, this command acts as a toggle: if +the characters at the beginning of the line do not match the value +of @code{comment-begin}, the value is inserted, otherwise +the characters in @code{comment-begin} are deleted from the beginning of +the line. +In either case, the line is accepted as if a newline had been typed. +@ifset BashFeatures +The default value of @code{comment-begin} causes this command +to make the current line a shell comment. +If a numeric argument causes the comment character to be removed, the line +will be executed by the shell. +@end ifset + +@item 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 @var{inputrc} file. This command is unbound by default. + +@item 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 @var{inputrc} file. This command is unbound by default. + +@item dump-macros () +Print all of the Readline key sequences bound to macros and the +strings they output. If a numeric argument is supplied, +the output is formatted in such a way that it can be made part +of an @var{inputrc} file. This command is unbound by default. + +@ifset BashFeatures +@item spell-correct-word (C-x s) +Perform spelling correction on the current word, treating it as a directory +or filename, in the same way as the @code{cdspell} shell option. +Word boundaries are the same as those used by @code{shell-forward-word}. + +@item glob-complete-word (M-g) +The word before point is treated as a pattern for pathname expansion, +with an asterisk implicitly appended. This pattern is used to +generate a list of matching file names for possible completions. + +@item glob-expand-word (C-x *) +The word before point is treated as a pattern for pathname expansion, +and the list of matching file names is inserted, replacing the word. +If a numeric argument is supplied, a @samp{*} is appended before +pathname expansion. + +@item glob-list-expansions (C-x g) +The list of expansions that would have been generated by +@code{glob-expand-word} is displayed, and the line is redrawn. +If a numeric argument is supplied, a @samp{*} is appended before +pathname expansion. + +@item display-shell-version (C-x C-v) +Display version information about the current instance of Bash. + +@item shell-expand-line (M-C-e) +Expand the line as the shell does. +This performs alias and history expansion as well as all of the shell +word expansions (@pxref{Shell Expansions}). + +@item history-expand-line (M-^) +Perform history expansion on the current line. + +@item magic-space () +Perform history expansion on the current line and insert a space +(@pxref{History Interaction}). + +@item alias-expand-line () +Perform alias expansion on the current line (@pxref{Aliases}). + +@item history-and-alias-expand-line () +Perform history and alias expansion on the current line. + +@item insert-last-argument (M-. or M-_) +A synonym for @code{yank-last-arg}. + +@item edit-and-execute-command (C-x C-e) +Invoke an editor on the current command line, and execute the result as shell +commands. +Bash attempts to invoke +@code{$VISUAL}, @code{$EDITOR}, and @code{emacs} +as the editor, in that order. + +@end ifset + +@ifclear BashFeatures +@item emacs-editing-mode (C-e) +When in @code{vi} command mode, this causes a switch to @code{emacs} +editing mode. + +@item vi-editing-mode (M-C-j) +When in @code{emacs} editing mode, this causes a switch to @code{vi} +editing mode. + +@end ifclear + +@end ftable + +@node Readline vi Mode +@section Readline vi Mode + +While the Readline library does not have a full set of @code{vi} +editing functions, it does contain enough to allow simple editing +of the line. The Readline @code{vi} mode behaves as specified in +the @sc{posix} standard. + +@ifset BashFeatures +In order to switch interactively between @code{emacs} and @code{vi} +editing modes, use the @samp{set -o emacs} and @samp{set -o vi} +commands (@pxref{The Set Builtin}). +@end ifset +@ifclear BashFeatures +In order to switch interactively between @code{emacs} and @code{vi} +editing modes, use the command @kbd{M-C-j} (bound to emacs-editing-mode +when in @code{vi} mode and to vi-editing-mode in @code{emacs} mode). +@end ifclear +The Readline default is @code{emacs} mode. + +When you enter a line in @code{vi} mode, you are already placed in +`insertion' mode, as if you had typed an @samp{i}. Pressing @key{ESC} +switches you into `command' mode, where you can edit the text of the +line with the standard @code{vi} movement keys, move to previous +history lines with @samp{k} and subsequent lines with @samp{j}, and +so forth. + +@ifset BashFeatures +@node Programmable Completion +@section Programmable Completion +@cindex programmable completion + +When word completion is attempted for an argument to a command for +which a completion specification (a @var{compspec}) has been defined +using the @code{complete} builtin (@pxref{Programmable Completion Builtins}), +the programmable completion facilities are invoked. + +First, the command name is identified. +If a compspec has been defined for that command, the +compspec is used to generate the list of possible completions for the word. +If the command word is the empty string (completion attempted at the +beginning of an empty line), any compspec defined with +the @option{-E} option to @code{complete} is used. +If the command word is a full pathname, a compspec for the full +pathname is searched for first. +If no compspec is found for the full pathname, an attempt is made to +find a compspec for the portion following the final slash. +If those searches do not result in a compspec, any compspec defined with +the @option{-D} option to @code{complete} is used as the default. +If there is no default compspec, Bash attempts alias expansion +on the command word as a final resort, and attempts to find a compspec +for the command word from any successful expansion + +Once a compspec has been found, it is used to generate the list of +matching words. +If a compspec is not found, the default Bash completion +described above (@pxref{Commands For Completion}) is performed. + +First, the actions specified by the compspec are used. +Only matches which are prefixed by the word being completed are +returned. +When the @option{-f} or @option{-d} option is used for filename or +directory name completion, the shell variable @env{FIGNORE} is +used to filter the matches. +@xref{Bash Variables}, for a description of @env{FIGNORE}. + +Any completions specified by a filename expansion pattern to the +@option{-G} option are generated next. +The words generated by the pattern need not match the word being completed. +The @env{GLOBIGNORE} shell variable is not used to filter the matches, +but the @env{FIGNORE} shell variable is used. + +Next, the string specified as the argument to the @option{-W} option +is considered. +The string is first split using the characters in the @env{IFS} +special variable as delimiters. +Shell quoting is honored within the string, in order to provide a +mechanism for the words to contain shell metacharacters or characters +in the value of @env{IFS}. +Each word is then expanded using +brace expansion, tilde expansion, parameter and variable expansion, +command substitution, and arithmetic expansion, +as described above (@pxref{Shell Expansions}). +The results are split using the rules described above +(@pxref{Word Splitting}). +The results of the expansion are prefix-matched against the word being +completed, and the matching words become the possible completions. + +After these matches have been generated, any shell function or command +specified with the @option{-F} and @option{-C} options is invoked. +When the command or function is invoked, the @env{COMP_LINE}, +@env{COMP_POINT}, @env{COMP_KEY}, and @env{COMP_TYPE} variables are +assigned values as described above (@pxref{Bash Variables}). +If a shell function is being invoked, the @env{COMP_WORDS} and +@env{COMP_CWORD} variables are also set. +When the function or command is invoked, the first argument ($1) is the +name of the command whose arguments are being completed, the +second argument ($2) is the word being completed, and the third argument +($3) is the word preceding the word being completed on the current command +line. +No filtering of the generated completions against the word being completed +is performed; the function or command has complete freedom in generating +the matches. + +Any function specified with @option{-F} is invoked first. +The function may use any of the shell facilities, including the +@code{compgen} and @code{compopt} builtins described below +(@pxref{Programmable Completion Builtins}), to generate the matches. +It must put the possible completions in the @env{COMPREPLY} array +variable, one per array element. + +Next, any command specified with the @option{-C} option is invoked +in an environment equivalent to command substitution. +It should print a list of completions, one per line, to +the standard output. +Backslash may be used to escape a newline, if necessary. + +After all of the possible completions are generated, any filter +specified with the @option{-X} option is applied to the list. +The filter is a pattern as used for pathname expansion; a @samp{&} +in the pattern is replaced with the text of the word being completed. +A literal @samp{&} may be escaped with a backslash; the backslash +is removed before attempting a match. +Any completion that matches the pattern will be removed from the list. +A leading @samp{!} negates the pattern; in this case any completion +not matching the pattern will be removed. +If the @code{nocasematch} shell option +(see the description of @code{shopt} in @ref{The Shopt Builtin}) +is enabled, the match is performed without regard to the case +of alphabetic characters. + +Finally, any prefix and suffix specified with the @option{-P} and @option{-S} +options are added to each member of the completion list, and the result is +returned to the Readline completion code as the list of possible +completions. + +If the previously-applied actions do not generate any matches, and the +@option{-o dirnames} option was supplied to @code{complete} when the +compspec was defined, directory name completion is attempted. + +If the @option{-o plusdirs} option was supplied to @code{complete} when +the compspec was defined, directory name completion is attempted and any +matches are added to the results of the other actions. + +By default, if a compspec is found, whatever it generates is returned to +the completion code as the full set of possible completions. +The default Bash completions are not attempted, and the Readline default +of filename completion is disabled. +If the @option{-o bashdefault} option was supplied to @code{complete} when +the compspec was defined, the default Bash completions are attempted +if the compspec generates no matches. +If the @option{-o default} option was supplied to @code{complete} when the +compspec was defined, Readline's default completion will be performed +if the compspec (and, if attempted, the default Bash completions) +generate no matches. + +When a compspec indicates that directory name completion is desired, +the programmable completion functions force Readline to append a slash +to completed names which are symbolic links to directories, subject to +the value of the @var{mark-directories} Readline variable, regardless +of the setting of the @var{mark-symlinked-directories} Readline variable. + +There is some support for dynamically modifying completions. This is +most useful when used in combination with a default completion specified +with @option{-D}. It's possible for shell functions executed as completion +handlers to indicate that completion should be retried by returning an +exit status of 124. If a shell function returns 124, and changes +the compspec associated with the command on which completion is being +attempted (supplied as the first argument when the function is executed), +programmable completion restarts from the beginning, with an +attempt to find a new compspec for that command. This allows a set of +completions to be built dynamically as completion is attempted, rather than +being loaded all at once. + +For instance, assuming that there is a library of compspecs, each kept in a +file corresponding to the name of the command, the following default +completion function would load completions dynamically: + +@example +_completion_loader() +@{ + . "/etc/bash_completion.d/$1.sh" >/dev/null 2>&1 && return 124 +@} +complete -D -F _completion_loader -o bashdefault -o default +@end example + +@node Programmable Completion Builtins +@section Programmable Completion Builtins +@cindex completion builtins + +Three builtin commands are available to manipulate the programmable completion +facilities: one to specify how the arguments to a particular command are to +be completed, and two to modify the completion as it is happening. + +@table @code +@item compgen +@btindex compgen +@example +@code{compgen [@var{option}] [@var{word}]} +@end example + +Generate possible completion matches for @var{word} according to +the @var{option}s, which may be any option accepted by the +@code{complete} +builtin with the exception of @option{-p} and @option{-r}, and write +the matches to the standard output. +When using the @option{-F} or @option{-C} options, the various shell variables +set by the programmable completion facilities, while available, will not +have useful values. + +The matches will be generated in the same way as if the programmable +completion code had generated them directly from a completion specification +with the same flags. +If @var{word} is specified, only those completions matching @var{word} +will be displayed. + +The return value is true unless an invalid option is supplied, or no +matches were generated. + +@item complete +@btindex complete +@example +@code{complete [-abcdefgjksuv] [-o @var{comp-option}] [-DEI] [-A @var{action}] [-G @var{globpat}] +[-W @var{wordlist}] [-F @var{function}] [-C @var{command}] [-X @var{filterpat}] +[-P @var{prefix}] [-S @var{suffix}] @var{name} [@var{name} @dots{}]} +@code{complete -pr [-DEI] [@var{name} @dots{}]} +@end example + +Specify how arguments to each @var{name} should be completed. +If the @option{-p} option is supplied, or if no options are supplied, existing +completion specifications are printed in a way that allows them to be +reused as input. +The @option{-r} option removes a completion specification for +each @var{name}, or, if no @var{name}s are supplied, all +completion specifications. +The @option{-D} option indicates that other supplied options and actions should +apply to the ``default'' command completion; that is, completion attempted +on a command for which no completion has previously been defined. +The @option{-E} option indicates that other supplied options and actions should +apply to ``empty'' command completion; that is, completion attempted on a +blank line. +The @option{-I} option indicates that other supplied options and actions should +apply to completion on the initial non-assignment word on the line, or after a +command delimiter such as @samp{;} or @samp{|}, which is usually command +name completion. +If multiple options are supplied, the @option{-D} option takes precedence +over @option{-E}, and both take precedence over @option{-I}. +If any of @option{-D}, @option{-E}, or @option{-I} are supplied, any other +@var{name} arguments are ignored; these completions only apply to the case +specified by the option. + +The process of applying these completion specifications when word completion +is attempted is described above (@pxref{Programmable Completion}). + +Other options, if specified, have the following meanings. +The arguments to the @option{-G}, @option{-W}, and @option{-X} options +(and, if necessary, the @option{-P} and @option{-S} options) +should be quoted to protect them from expansion before the +@code{complete} builtin is invoked. + + +@table @code +@item -o @var{comp-option} +The @var{comp-option} controls several aspects of the compspec's behavior +beyond the simple generation of completions. +@var{comp-option} may be one of: + +@table @code + +@item bashdefault +Perform the rest of the default Bash completions if the compspec +generates no matches. + +@item default +Use Readline's default filename completion if the compspec generates +no matches. + +@item dirnames +Perform directory name completion if the compspec generates no matches. + +@item filenames +Tell Readline that the compspec generates filenames, so it can perform any +filename-specific processing (like adding a slash to directory names, +quoting special characters, or suppressing trailing spaces). +This option is intended to be used with shell functions specified +with @option{-F}. + +@item noquote +Tell Readline not to quote the completed words if they are filenames +(quoting filenames is the default). + +@item nosort +Tell Readline not to sort the list of possible completions alphabetically. + +@item nospace +Tell Readline not to append a space (the default) to words completed at +the end of the line. + +@item plusdirs +After any matches defined by the compspec are generated, +directory name completion is attempted and any +matches are added to the results of the other actions. + +@end table + +@item -A @var{action} +The @var{action} may be one of the following to generate a list of possible +completions: + +@table @code +@item alias +Alias names. May also be specified as @option{-a}. + +@item arrayvar +Array variable names. + +@item binding +Readline key binding names (@pxref{Bindable Readline Commands}). + +@item builtin +Names of shell builtin commands. May also be specified as @option{-b}. + +@item command +Command names. May also be specified as @option{-c}. + +@item directory +Directory names. May also be specified as @option{-d}. + +@item disabled +Names of disabled shell builtins. + +@item enabled +Names of enabled shell builtins. + +@item export +Names of exported shell variables. May also be specified as @option{-e}. + +@item file +File names. May also be specified as @option{-f}. + +@item function +Names of shell functions. + +@item group +Group names. May also be specified as @option{-g}. + +@item helptopic +Help topics as accepted by the @code{help} builtin (@pxref{Bash Builtins}). + +@item hostname +Hostnames, as taken from the file specified by the +@env{HOSTFILE} shell variable (@pxref{Bash Variables}). + +@item job +Job names, if job control is active. May also be specified as @option{-j}. + +@item keyword +Shell reserved words. May also be specified as @option{-k}. + +@item running +Names of running jobs, if job control is active. + +@item service +Service names. May also be specified as @option{-s}. + +@item setopt +Valid arguments for the @option{-o} option to the @code{set} builtin +(@pxref{The Set Builtin}). + +@item shopt +Shell option names as accepted by the @code{shopt} builtin +(@pxref{Bash Builtins}). + +@item signal +Signal names. + +@item stopped +Names of stopped jobs, if job control is active. + +@item user +User names. May also be specified as @option{-u}. + +@item variable +Names of all shell variables. May also be specified as @option{-v}. +@end table + +@item -C @var{command} +@var{command} is executed in a subshell environment, and its output is +used as the possible completions. +Arguments are passed as with the @option{-F} option. + +@item -F @var{function} +The shell function @var{function} is executed in the current shell +environment. +When it is executed, $1 is the name of the command whose arguments are +being completed, $2 is the word being completed, and $3 is the word +preceding the word being completed, as described above +(@pxref{Programmable Completion}). +When it finishes, the possible completions are retrieved from the value +of the @env{COMPREPLY} array variable. + +@item -G @var{globpat} +The filename expansion pattern @var{globpat} is expanded to generate +the possible completions. + +@item -P @var{prefix} +@var{prefix} is added at the beginning of each possible completion +after all other options have been applied. + +@item -S @var{suffix} +@var{suffix} is appended to each possible completion +after all other options have been applied. + +@item -W @var{wordlist} +The @var{wordlist} is split using the characters in the +@env{IFS} special variable as delimiters, and each resultant word +is expanded. +The possible completions are the members of the resultant list which +match the word being completed. + +@item -X @var{filterpat} +@var{filterpat} is a pattern as used for filename expansion. +It is applied to the list of possible completions generated by the +preceding options and arguments, and each completion matching +@var{filterpat} is removed from the list. +A leading @samp{!} in @var{filterpat} negates the pattern; in this +case, any completion not matching @var{filterpat} is removed. +@end table + +The return value is true unless an invalid option is supplied, an option +other than @option{-p} or @option{-r} is supplied without a @var{name} +argument, an attempt is made to remove a completion specification for +a @var{name} for which no specification exists, or +an error occurs adding a completion specification. + +@item compopt +@btindex compopt +@example +@code{compopt} [-o @var{option}] [-DEI] [+o @var{option}] [@var{name}] +@end example +Modify completion options for each @var{name} according to the +@var{option}s, or for the currently-executing completion if no @var{name}s +are supplied. +If no @var{option}s are given, display the completion options for each +@var{name} or the current completion. +The possible values of @var{option} are those valid for the @code{complete} +builtin described above. +The @option{-D} option indicates that other supplied options should +apply to the ``default'' command completion; that is, completion attempted +on a command for which no completion has previously been defined. +The @option{-E} option indicates that other supplied options should +apply to ``empty'' command completion; that is, completion attempted on a +blank line. +The @option{-I} option indicates that other supplied options should +apply to completion on the initial non-assignment word on the line, or after a +command delimiter such as @samp{;} or @samp{|}, which is usually command +name completion. + +If multiple options are supplied, the @option{-D} option takes precedence +over @option{-E}, and both take precedence over @option{-I} + +The return value is true unless an invalid option is supplied, an attempt +is made to modify the options for a @var{name} for which no completion +specification exists, or an output error occurs. + +@end table + +@node A Programmable Completion Example +@section A Programmable Completion Example + +The most common way to obtain additional completion functionality beyond +the default actions @code{complete} and @code{compgen} provide is to use +a shell function and bind it to a particular command using @code{complete -F}. + +The following function provides completions for the @code{cd} builtin. +It is a reasonably good example of what shell functions must do when +used for completion. This function uses the word passed as @code{$2} +to determine the directory name to complete. You can also use the +@code{COMP_WORDS} array variable; the current word is indexed by the +@code{COMP_CWORD} variable. + +The function relies on the @code{complete} and @code{compgen} builtins +to do much of the work, adding only the things that the Bash @code{cd} +does beyond accepting basic directory names: +tilde expansion (@pxref{Tilde Expansion}), +searching directories in @var{$CDPATH}, which is described above +(@pxref{Bourne Shell Builtins}), +and basic support for the @code{cdable_vars} shell option +(@pxref{The Shopt Builtin}). +@code{_comp_cd} modifies the value of @var{IFS} so that it contains only +a newline to accommodate file names containing spaces and tabs -- +@code{compgen} prints the possible completions it generates one per line. + +Possible completions go into the @var{COMPREPLY} array variable, one +completion per array element. The programmable completion system retrieves +the completions from there when the function returns. + +@example +# A completion function for the cd builtin +# based on the cd completion function from the bash_completion package +_comp_cd() +@{ + local IFS=$' \t\n' # normalize IFS + local cur _skipdot _cdpath + local i j k + + # Tilde expansion, which also expands tilde to full pathname + case "$2" in + \~*) eval cur="$2" ;; + *) cur=$2 ;; + esac + + # no cdpath or absolute pathname -- straight directory completion + if [[ -z "$@{CDPATH:-@}" ]] || [[ "$cur" == @@(./*|../*|/*) ]]; then + # compgen prints paths one per line; could also use while loop + IFS=$'\n' + COMPREPLY=( $(compgen -d -- "$cur") ) + IFS=$' \t\n' + # CDPATH+directories in the current directory if not in CDPATH + else + IFS=$'\n' + _skipdot=false + # preprocess CDPATH to convert null directory names to . + _cdpath=$@{CDPATH/#:/.:@} + _cdpath=$@{_cdpath//::/:.:@} + _cdpath=$@{_cdpath/%:/:.@} + for i in $@{_cdpath//:/$'\n'@}; do + if [[ $i -ef . ]]; then _skipdot=true; fi + k="$@{#COMPREPLY[@@]@}" + for j in $( compgen -d -- "$i/$cur" ); do + COMPREPLY[k++]=$@{j#$i/@} # cut off directory + done + done + $_skipdot || COMPREPLY+=( $(compgen -d -- "$cur") ) + IFS=$' \t\n' + fi + + # variable names if appropriate shell option set and no completions + if shopt -q cdable_vars && [[ $@{#COMPREPLY[@@]@} -eq 0 ]]; then + COMPREPLY=( $(compgen -v -- "$cur") ) + fi + + return 0 +@} +@end example + +We install the completion function using the @option{-F} option to +@code{complete}: + +@example +# Tell readline to quote appropriate and append slashes to directories; +# use the bash default completion for other arguments +complete -o filenames -o nospace -o bashdefault -F _comp_cd cd +@end example + +@noindent +Since we'd like Bash and Readline to take care of some +of the other details for us, we use several other options to tell Bash +and Readline what to do. The @option{-o filenames} option tells Readline +that the possible completions should be treated as filenames, and quoted +appropriately. That option will also cause Readline to append a slash to +filenames it can determine are directories (which is why we might want to +extend @code{_comp_cd} to append a slash if we're using directories found +via @var{CDPATH}: Readline can't tell those completions are directories). +The @option{-o nospace} option tells Readline to not append a space +character to the directory name, in case we want to append to it. +The @option{-o bashdefault} option brings in the rest of the "Bash default" +completions -- possible completions that Bash adds to the default Readline +set. These include things like command name completion, variable completion +for words beginning with @samp{$} or @samp{$@{}, completions containing pathname +expansion patterns (@pxref{Filename Expansion}), and so on. + +Once installed using @code{complete}, @code{_comp_cd} will be called every +time we attempt word completion for a @code{cd} command. + +Many more examples -- an extensive collection of completions for most of +the common GNU, Unix, and Linux commands -- are available as part of the +bash_completion project. This is installed by default on many GNU/Linux +distributions. Originally written by Ian Macdonald, the project now lives +at @url{https://github.com/scop/bash-completion/}. There are ports for +other systems such as Solaris and Mac OS X. + +An older version of the bash_completion package is distributed with bash +in the @file{examples/complete} subdirectory. + +@end ifset |