READLINE(3)

NAME
readline - get a line from a user with editing

SYNOPSIS

#include <stdio.h>
#include <readline/readline.h>
#include <readline/history.h>

char *
readline (const char *prompt);

COPYRIGHT
Readline is Copyright (C) 1989-2025 Free Software Foundation, Inc.

DESCRIPTION

readline reads a line from the terminal and return it, using prompt as a prompt. If prompt is NULL or the empty string, readline does not issue a prompt. The line returned is allocated with malloc(3); the caller must free it when finished. The line returned has the final newline removed, so only the text of the line remains. Since it's possible to enter characters into the line while quoting them to disable any readline editing function they might normally have, this line may include embedded newlines and other special characters.

readline offers editing capabilities while the user is entering the line. By default, the line editing commands are similar to those of emacs. A vi-style line editing interface is also available.

This manual page describes only the most basic use of readline. Much more functionality is available; see The GNU Readline Library and The GNU History Library for additional information.

RETURN VALUE

readline returns the text of the line read. A blank line returns the empty string. If EOF is encountered while reading a line, and the line is empty, readline returns NULL. If an EOF is read with a non-empty line, it is treated as a newline.

NOTATION

This section uses Emacs-style editing concepts and uses its notation for keystrokes. Control keys are denoted by C-key, e.g., C-n means Control-N. Similarly, meta keys are denoted by M-key, so M-x means Meta-X. The Meta key is often labeled or

On keyboards without a Meta key, M-x means ESC x, i.e., press and release the Escape key, then press and release the x key, in sequence. This makes ESC the meta prefix. The combination M-C-x means ESC Control-x: press and release the Escape key, then press and hold the Control key while pressing the x key, then release both.

On some keyboards, the Meta key modifier produces characters with the eighth bit (0200) set. You can use the enable-meta-key variable to control whether or not it does this, if the keyboard allows it. On many others, the terminal or terminal emulator converts the metafied key to a key sequence beginning with ESC as described in the preceding paragraph.

If your Meta key produces a key sequence with the ESC meta prefix, you can make M-key key bindings you specify (see Readline Key Bindings below) do the same thing by setting the force-meta-prefix variable.

Readline commands may be given numeric arguments, which normally act as a repeat count. Sometimes, however, it is the sign of the argument that is significant. Passing a negative argument to a command that acts in the forward direction (e.g., kill-line) makes that command act in a backward direction. Commands whose behavior with arguments deviates from this are noted below.

The point is the current cursor position, and mark refers to a saved cursor position. The text between the point and mark is referred to as the region.

When a command is described as killing text, the text deleted is saved for possible future retrieval (yanking). The killed text is saved in a kill ring. Consecutive kills accumulate the deleted text into one unit, which can be yanked all at once. Commands which do not kill text separate the chunks of text on the kill ring.

INITIALIZATION FILE

Readline is customized by putting commands in an initialization file (the inputrc file). The name of this file is taken from the value of the INPUTRC environment variable. If that variable is unset, the default is ~/.inputrc. If that file does not exist or cannot be read, readline looks for /etc/inputrc. When a program that uses the readline library starts up, readline reads the initialization file and sets the key bindings and variables found there, before reading any user input.

There are only a few basic constructs allowed in the inputrc file. Blank lines are ignored. Lines beginning with a # are comments. Lines beginning with a $ indicate conditional constructs. Other lines denote key bindings and variable settings.

The default key-bindings in this document may be changed using key binding commands in the inputrc file. Programs that use this library may add their own commands and bindings.

For example, placing

    M-Control-u: universal-argument
or
    C-Meta-u: universal-argument

into the inputrc would make M-C-u execute the readline command universal-argument.

Key bindings may contain the following symbolic character names: DEL, ESC, ESCAPE, LFD, NEWLINE, RET, RETURN, RUBOUT (a destructive backspace), SPACE, SPC, and TAB.

In addition to command names, readline allows keys to be bound to a string that is inserted when the key is pressed (a macro). The difference between a macro and a command is that a macro is enclosed in single or double quotes.

  Key Bindings
The syntax for controlling key bindings in the inputrc file is simple. All that is required is the name of the command or the text of a macro and a key sequence to which it should be bound. The key sequence may be specified in one of two ways: as a symbolic key name, possibly with Meta- or Control- prefixes, or as a key sequence composed of one or more characters enclosed in double quotes. The key sequence and name are separated by a colon. There can be no whitespace between the name and the colon.

When using the form keyname:function-name or macro, keyname is the name of a key spelled out in English. For example:

        Control-u: universal-argument
        Meta-Rubout: backward-kill-word
        Control-o: "> output"

In the above example, C-u is bound to the function universal-argument, M-DEL is bound to the function backward-kill-word, and C-o is bound to run the macro expressed on the right hand side (that is, to insert the text into the line).

In the second form, "keyseq":function-name or macro, keyseq differs from keyname above in that strings denoting an entire key sequence may be specified by placing the sequence within double quotes. Some GNU Emacs style key escapes can be used, as in the following example, but none of the symbolic character names are recognized.

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

In this example, C-u is again bound to the function universal-argument. C-x C-r is bound to the function re-read-init-file, and ESC [ 1 1 ~ is bound to insert the text

The full set of GNU Emacs style escape sequences available when specifying key sequences is
    \C- A control prefix.
    \M- Adding the meta prefix or converting the following character to a meta character, as described below under force-meta-prefix.
    \e  An escape character.
    \\  Backslash.
    \"  Literal ", a double quote.
    \'  Literal ', a single quote.

In addition to the GNU Emacs style escape sequences, a second set of backslash escapes is available:
    \a  alert (bell)
    \b  backspace
    \d  delete
    \f  form feed
    \n  newline
    \r  carriage return
    \t  horizontal tab
    \v  vertical tab
    \nnn
        The eight-bit character whose value is the octal value nnn (one to three digits).
    \xHH
        The eight-bit character whose value is the hexadecimal value HH (one or two hex digits).

When entering the text of a macro, single or double quotes must be used to indicate a macro definition. Unquoted text is assumed to be a function name. The backslash escapes described above are expanded in the macro body. Backslash quotes any other character in the macro text, including " and '.

Bash will display or modify the current readline key bindings with the bind builtin command. The -o emacs or -o vi options to the set builtin change the editing mode during interactive use. Other programs using this library provide similar mechanisms. A user may always edit the inputrc file and have readline re-read it if a program does not provide any other means to incorporate new bindings.

  Variables
Readline has variables that can be used to further customize its behavior. A variable may be set in the inputrc file with a statement of the form

    set variable-name value

Except where noted, readline variables can take the values On or Off (without regard to case). Unrecognized variable names are ignored. When readline reads a variable value, empty or null values, (case-insensitive), and are equivalent to On. All other values are equivalent to Off.

The variables and their default values are:

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 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
active-region-end-color
    A string variable that the effects of active-region-start-color and restores 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
bell-style (audible)
    Controls what happens when readline wants to ring the terminal bell. If set to none, readline never rings the bell. If set to visible, readline uses a visible bell if one is available. If set to audible, readline attempts to ring the terminal's bell.
bind-tty-special-chars (On)
    If set to On, readline attempts to bind the control characters that are treated specially by the kernel's terminal driver to their readline equivalents. These override the default readline bindings described here. Type at a bash prompt to see your current terminal settings, including the special control characters (usually cchars).
blink-matching-paren (Off)
    If set to On, readline attempts to briefly move the cursor to an opening parenthesis when a closing parenthesis is inserted.
colored-completion-prefix (Off)
    If set to 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 LS_COLORS environment variable. If there is a color definition in $LS_COLORS for the custom suffix readline uses this color for the common prefix instead of its default.
colored-stats (Off)
    If set to On, readline displays possible completions using different colors to indicate their file type. The color definitions are taken from the value of the LS_COLORS environment variable.
comment-begin (
    The string that the readline insert-comment command inserts. This command is bound to M-# in emacs mode and to # in vi command mode.
completion-display-width (-1)
    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 causes matches to be displayed one per line. The default value is -1.
completion-ignore-case (Off)
    If set to On, readline performs filename matching and completion in a case-insensitive fashion.
completion-map-case (Off)
    If set to On, and completion-ignore-case is enabled, readline treats hyphens (-) and underscores (_) as equivalent when performing case-insensitive filename matching and completion.
completion-prefix-display-length (0)
    The maximum 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, readline replaces common prefixes longer than this value with an ellipsis when displaying possible completions. If a completion begins with a period, and eadline is completing filenames, it uses three underscores instead of an ellipsis.
completion-query-items (100)
    This determines when the user is queried about viewing the number of possible completions generated by the possible-completions command. It may be set to any integer value greater than or equal to zero. If the number of possible completions is greater than or equal to the value of this variable, readline asks whether or not the user wishes to view them; otherwise readline simply lists them on the terminal. A zero value means readline should never ask; negative values are treated as zero.
convert-meta (On)
    If set to On, readline converts characters it reads that have the eighth bit set to an ASCII key sequence by clearing the eighth bit and prefixing it with an escape character (converting the character to have the meta prefix). The default is On, but readline sets it to Off if the locale contains characters whose encodings may include bytes with the eighth bit set. This variable is dependent on the LC_CTYPE locale category, and may change if the locale changes. This variable also affects key bindings; see the description of force-meta-prefix below.
disable-completion (Off)
    If set to On, readline inhibits word completion. Completion characters are inserted into the line as if they had been mapped to self-insert.
echo-control-characters (On)
    When set to On, on operating systems that indicate they support it, readline echoes a character corresponding to a signal generated from the keyboard.
editing-mode (emacs)
    Controls whether readline uses a set of key bindings similar to Emacs or vi. editing-mode can be set to either emacs or vi.
emacs-mode-string (@)
    If the 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. The \1 and \2 escapes begin and end sequences of non-printing characters, which can be used to embed a terminal control sequence into the mode string.
enable-active-region (On)
    When this variable is set to On, readline allows certain commands to designate the region as active. When the region is active, readline highlights the text in the region using the value of the active-region-start-color variable, 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.
enable-bracketed-paste (On)
    When set to 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 bracketed-paste mode; it prevents readline from executing any editing commands bound to key sequences appearing in the pasted text.
enable-keypad (Off)
    When set to On, readline tries to enable the application keypad when it is called. Some systems need this to enable the arrow keys.
enable-meta-key (On)
    When set to On, readline tries to enable any meta modifier key the terminal claims to support. On many terminals, the Meta key is used to send eight-bit characters; this variable checks for the terminal capability that indicates the terminal can enable and disable a mode that sets the eighth bit of a character (0200) if the Meta key is held down when the character is typed (a meta character).
expand-tilde (Off)
    If set to On, readline performs tilde expansion when it attempts word completion.
force-meta-prefix (Off)
    If set to On, readline modifies its behavior when binding key sequences containing \M- or Meta- (see Key Bindings above) by converting a key sequence of the form \M-C or Meta-C to the two-character sequence ESC C (adding the meta prefix). If force-meta-prefix is set to Off (the default), readline uses the value of the convert-meta variable to determine whether to perform this conversion: if convert-meta is On, readline performs the conversion described above; if it is Off, readline converts C to a meta character by setting the eighth bit (0200).
history-preserve-point (Off)
    If set to On, the history code attempts to place point at the same location on each history line retrieved with previous-history or next-history.
history-size (unset)
    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. Setting history-size to a non-numeric value will set the maximum number of history entries to 500.
horizontal-scroll-mode (Off)
    Setting this variable to On makes readline use a single line for display, scrolling the input horizontally on a single screen line when it becomes longer than the screen width rather than wrapping to a new line. This setting is automatically enabled for terminals of height 1.
input-meta (Off)
    If set to On, readline enables eight-bit input (that is, it does not clear the eighth bit in the characters it reads), regardless of what the terminal claims it can support. The default is Off, but readline sets it to On if the locale contains characters whose encodings may include bytes with the eighth bit set. This variable is dependent on the LC_CTYPE locale category, and its value may change if the locale changes. The name meta-flag is a synonym for input-meta.
isearch-terminators (
    The string of characters that should terminate an incremental search without subsequently executing the character as a command. If this variable has not been given a value, the characters ESC and C-j terminate an incremental search.
keymap (emacs)
    Set the current readline keymap. The set of valid keymap names is emacs, emacs-standard, emacs-meta, emacs-ctlx, vi, vi-command, and vi-insert. vi is equivalent to vi-command; emacs is equivalent to emacs-standard. The default value is emacs; the value of editing-mode also affects the default keymap.
keyseq-timeout (500)
    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 readline does not receive any input within the timeout, it uses the shorter but complete key sequence. 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 waits until another key is pressed to decide which key sequence to complete.
mark-directories (On)
    If set to On, completed directory names have a slash appended.
mark-modified-lines (Off)
    If set to On, readline displays history lines that have been modified with a preceding asterisk (*).
mark-symlinked-directories (Off)
    If set to On, completed names which are symbolic links to directories have a slash appended, subject to the value of mark-directories.
match-hidden-files (On)
    This variable, when set to On, forces readline to match files whose names begin with a (hidden files) when performing filename completion. If set to Off, the user must include the leading in the filename to be completed.
menu-complete-display-prefix (Off)
    If set to On, menu completion displays the common prefix of the list of possible completions (which may be empty) before cycling through the list.
output-meta (Off)
    If set to On, readline displays characters with the eighth bit set directly rather than as a meta-prefixed escape sequence. The default is Off, but readline sets it to On if the locale contains characters whose encodings may include bytes with the eighth bit set. This variable is dependent on the LC_CTYPE locale category, and its value may change if the locale changes.
page-completions (On)
    If set to On, readline uses an internal pager resembling more(1) to display a screenful of possible completions at a time.
prefer-visible-bell
    See bell-style.
print-completions-horizontally (Off)
    If set to On, readline displays completions with matches sorted horizontally in alphabetical order, rather than down the screen.
revert-all-at-newline (Off)
    If set to On, readline will undo all changes to history lines before returning when executing accept-line. By default, history lines may be modified and retain individual undo lists across calls to readline().
search-ignore-case (Off)
    If set to On, readline performs incremental and non-incremental history list searches in a case-insensitive fashion.
show-all-if-ambiguous (Off)
    This alters the default behavior of the completion functions. If set to On, words which have more than one possible completion cause the matches to be listed immediately instead of ringing the bell.
show-all-if-unmodified (Off)
    This alters the default behavior of the completion functions in a fashion similar to show-all-if-ambiguous. If set to 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.
show-mode-in-prompt (Off)
    If set to 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., emacs-mode-string).
skip-completed-text (Off)
    If set to 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.
vi-cmd-mode-string ((cmd))
    If the 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. The \1 and \2 escapes begin and end sequences of non-printing characters, which can be used to embed a terminal control sequence into the mode string.
vi-ins-mode-string ((ins))
    If the 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. The \1 and \2 escapes begin and end sequences of non-printing characters, which can be used to embed a terminal control sequence into the mode string.
visible-stats (Off)
    If set to On, a character denoting a file's type as reported by stat(2) is appended to the filename when listing possible completions.

  Conditional 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 available.

$if The $if construct allows bindings to be made based on the editing mode, the terminal being used, or the application using readline. The text of the test, after any comparison operator, extends to the end of the line; unless otherwise noted, no characters are required to isolate it.

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

    term
        The term= form may be used to include terminal-specific key bindings, perhaps to bind the key sequences output by the terminal's function keys. The word on the right side of the = is tested against both the full name of the terminal and the portion of the terminal name before the first -. This allows xterm to match both xterm and xterm-256color, for instance.

    version
        The version test may be used to perform comparisons against specific readline versions. The version expands to the current readline version. The set of comparison operators includes =, (and ==), !=, <=, >=, <, and >. 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., 7.1). If the minor version is omitted, it defaults to 0. The operator may be separated from the string version and from the version number argument by whitespace.

    application
        The application construct is used to include application-specific settings. Each program using the readline library sets the application name, and an initialization file 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:

            $if Bash
            # Quote the current or previous word
            "\C-xq": "\eb\"\ef\""
            $endif

    variable
        The variable construct provides simple equality tests for readline variables and values. The permitted comparison operators are =, ==, and !=. 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. String and boolean variables may be tested. Boolean variables must be tested against the values on and off.

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

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

$include
    This directive takes a single filename as an argument and reads commands and key bindings from that file. For example, the following directive would read /etc/inputrc:

    $include  /etc/inputrc

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

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

To find other matching entries in the history list, type C-r or C-s as appropriate. This searches 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 terminates the search and executes that command. For instance, a newline terminates the search and accepts 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 C-rs are typed without any intervening characters defining a new search string, readline uses any remembered search string.

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

EDITING COMMANDS
The following is a list of the names of the commands and the default key sequences to which they are bound. Command names without an accompanying key sequence are unbound by default.

In the following descriptions, point refers to the current cursor position, and mark refers to a cursor position saved by the set-mark command. The text between the point and mark is referred to as the region. Readline has the concept of an active region: when the region is active, readline redisplay highlights the region using the value of the active-region-start-color variable. The enable-active-region variable turns this on and off. Several commands set the region to active; those are noted below.

  Commands for Moving
beginning-of-line (C-a)
    Move to the start of the current line. This may also be bound to the Home key on some keyboards.
end-of-line (C-e)
    Move to the end of the line. This may also be bound to the End key on some keyboards.
forward-char (C-f)
    Move forward a character. This may also be bound to the right arrow key on some keyboards.
backward-char (C-b)
    Move back a character.
forward-word (M-f)
    Move forward to the end of the next word. Words are composed of alphanumeric characters (letters and digits).
backward-word (M-b)
    Move back to the start of the current or previous word. Words are composed of alphanumeric characters (letters and digits).
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.
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.
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.
clear-screen (C-l)
    Clear the screen, then redraw the current line, leaving the current line at the top of the screen. With a numeric argument, refresh the current line without clearing the screen.
redraw-current-line
    Refresh the current line.

  Commands for Manipulating the History
accept-line (Newline, Return)
    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 add_history(). If the line is a modified history line, restore the history line to its original state.
previous-history (C-p)
    Fetch the previous command from the history list, moving back in the list. This may also be bound to the up arrow key on some keyboards.
next-history (C-n)
    Fetch the next command from the history list, moving forward in the list. This may also be bound to the down arrow key on some keyboards.
beginning-of-history (M-<)
    Move to the first line in the history.
end-of-history (M->)
    Move to the end of the input history, i.e., the line currently being entered.
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.
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.
reverse-search-history (C-r)
    Search backward starting at the current line and moving through the history as necessary. This is an incremental search. This command sets the region to the matched text and activates the region.
forward-search-history (C-s)
    Search forward starting at the current line and moving through the history as necessary. This is an incremental search. This command sets the region to the matched text and activates the region.
non-incremental-reverse-search-history (M-p)
    Search backward through the history starting at the current line using a non-incremental search for a string supplied by the user. The search string may match anywhere in a history line.
non-incremental-forward-search-history (M-n)
    Search forward through the history using a non-incremental search for a string supplied by the user. The search string may match anywhere in a history line.
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. This may be bound to the Page Up key on some keyboards.
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. This may be bound to the Page Down key on some keyboards.
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.
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.
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 n, insert the nth word from the previous command (the words in the previous command begin with word 0). A negative argument inserts the nth word from the end of the previous command. Once the argument n is computed, this uses the history expansion facilities to extract the nth word, as if the history expansion had been specified.
yank-last-arg (M-., M-_)
    Insert the last argument to the previous command (the last word of the previous history entry). With a numeric argument, behave exactly like yank-nth-arg. Successive calls to 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). This uses the history expansion facilities to extract the last word, as if the history expansion had been specified.

  Commands for Changing Text
end-of-file (usually C-d)
    The character indicating end-of-file as set, for example, by stty(1). 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 EOF.
delete-char (C-d)
    Delete the character at point. If this function is bound to the same character as the tty EOF character, as C-d commonly is, see above for the effects. This may also be bound to the Delete key on some keyboards.
backward-delete-char (Rubout)
    Delete the character behind the cursor. When given a numeric argument, save the deleted text on the kill ring.
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.
quoted-insert (C-q, C-v)
    Add the next character typed to the line verbatim. This is how to insert characters like C-q, for example.
tab-insert (M-TAB)
    Insert a tab character.
self-insert (a, b, A, 1, !, ...)
    Insert the character typed.
bracketed-paste-begin
    This function is intended to be bound to the 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 pasted characters are inserted as if each one was bound to self-insert instead of executing any editing commands.
    Bracketed paste sets the region to the inserted text and activates the region.
transpose-chars (C-t)
    Drag the character before point forward over the character at point, moving point forward as well. If point is at the end of the line, then this transposes the two characters before point. Negative arguments have no effect.
transpose-words (M-t)
    Drag the word before point past the word after point, moving point past that word as well. If point is at the end of the line, this transposes the last two words on the line.
upcase-word (M-u)
    Uppercase the current (or following) word. With a negative argument, uppercase the previous word, but do not move point.
downcase-word (M-l)
    Lowercase the current (or following) word. With a negative argument, lowercase the previous word, but do not move point.
capitalize-word (M-c)
    Capitalize the current (or following) word. With a negative argument, capitalize the previous word, but do not move point.
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 emacs mode; vi mode does overwrite differently. Each call to readline() starts in insert mode.
    In overwrite mode, characters bound to self-insert replace the text at point rather than pushing the text to the right. Characters bound to backward-delete-char replace the character before point with a space. By default, this command is unbound, but may be bound to the Insert key on some keyboards.

  Killing and Yanking
kill-line (C-k)
    Kill the text from point to the end of the current line. With a negative numeric argument, kill backward from the cursor to the beginning of the line.
backward-kill-line (C-x Rubout)
    Kill backward to the beginning of the current line. With a negative numeric argument, kill forward from the cursor to the end of the line.
unix-line-discard (C-u)
    Kill backward from point to the beginning of the line, saving the killed text on the kill-ring.
kill-whole-line
    Kill all characters on the current line, no matter where point is.
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 those used by forward-word.
backward-kill-word (M-Rubout)
    Kill the word behind point. Word boundaries are the same as those used by backward-word.
unix-word-rubout (C-w)
    Kill the word behind point, using white space as a word boundary, saving the killed text on the kill-ring.
unix-filename-rubout
    Kill the word behind point, using white space and the slash character as the word boundaries, saving the killed text on the kill-ring.
delete-horizontal-space (M-\)
    Delete all spaces and tabs around point.
kill-region
    Kill the text in the current region.
copy-region-as-kill
    Copy the text in the region to the kill buffer, so it can be yanked immediately.
copy-backward-word
    Copy the word before point to the kill buffer. The word boundaries are the same as backward-word.
copy-forward-word
    Copy the word following point to the kill buffer. The word boundaries are the same as forward-word.
yank (C-y)
    Yank the top of the kill ring into the buffer at point.
yank-pop (M-y)
    Rotate the kill ring, and yank the new top. Only works following yank or yank-pop.

  Numeric Arguments
digit-argument (M-0, M-1, ..., M--)
    Add this digit to the argument already accumulating, or start a new argument. M-- starts a negative argument.
universal-argument
    This is another way to specify an argument. If this command is followed by one or more digits, optionally with a leading minus sign, those digits define the argument. If the command is followed by digits, executing universal-argument again ends the numeric argument, but is otherwise ignored. As a special case, if this command is immediately followed by a character that is neither a digit 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.

  Completing
complete (TAB)
    Attempt to perform completion on the text before point. The actual completion performed is application-specific. Bash, for instance, attempts programmable completion first, otherwise treating the text as a variable (if the text begins with $), username (if the text begins with ~), hostname (if the text begins with @), or command (including aliases, functions, and builtins) in turn. If none of these produces a match, it falls back to filename completion. Gdb, on the other hand, allows completion of program functions and variables, and only attempts filename completion under certain circumstances. The default readline completion is filename completion.
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 completion-display-width, the value of the environment variable COLUMNS, or the screen width, in that order.
insert-completions (M-*)
    Insert all completions of the text before point that would have been generated by possible-completions, separated by a space.
menu-complete
    Similar to complete, but replaces the word to be completed with a single match from the list of possible completions. Repeatedly executing menu-complete steps through the list of possible completions, inserting each match in turn. At the end of the list of completions, menu-complete rings the bell (subject to the setting of bell-style) and restores the original text. An argument of n moves n positions forward in the list of matches; a negative argument moves backward through the list. This command is intended to be bound to TAB, but is unbound by default.
menu-complete-backward
    Identical to menu-complete, but moves backward through the list of possible completions, as if menu-complete had been given a negative argument. This command is unbound by default.
export-completions
    Perform completion on the word before point as described above and write the list of possible completions to readline's output stream using the following format, writing information on separate lines:

    •   the number of matches N;
    •   the word being completed;
    •   S:E, where S and E are the start and end offsets of the word in the readline line buffer; then
    •   each match, one per line

    If there are no matches, the first line will be and this command does not print any output after the S:E. If there is only a single match, this prints a single line containing it. If there is more than one match, this prints the common prefix of the matches, which may be empty, on the first line after the S:E, then the matches on subsequent lines. In this case, N will include the first line with the common prefix.

    The user or application should be able to accommodate the possibility of a blank line. The intent is that the user or application reads N lines after the line containing S:E to obtain the match list. This command is unbound by default.

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

  Keyboard Macros
start-kbd-macro (C-x ()
    Begin saving the characters typed into the current keyboard macro.
end-kbd-macro (C-x ))
    Stop saving the characters typed into the current keyboard macro and store the definition.
call-last-kbd-macro (C-x e)
    Re-execute the last keyboard macro defined, by making the characters in the macro appear as if typed at the keyboard.
print-last-kbd-macro ()
    Print the last keyboard macro defined in a format suitable for the inputrc file.

  Miscellaneous
re-read-init-file (C-x C-r)
    Read in the contents of the inputrc file, and incorporate any bindings or variable assignments found there.
abort (C-g)
    Abort the current editing command and ring the terminal's bell (subject to the setting of bell-style).
do-lowercase-version (M-A, M-B, M-x, ...)
    If the metafied character x is uppercase, run the command that is bound to the corresponding metafied lowercase character. The behavior is undefined if x is already lowercase.
prefix-meta (ESC)
    Metafy the next character typed. ESC f is equivalent to Meta-f.
undo (C-_, C-x C-u)
    Incremental undo, separately remembered for each line.
revert-line (M-r)
    Undo all changes made to this line. This is like executing the undo command enough times to return the line to its initial state.
tilde-expand (M-~)
    Perform tilde expansion on the current word.
set-mark (C-@, M-<space>)
    Set the mark to the point. If a numeric argument is supplied, set the mark to that position.
exchange-point-and-mark (C-x C-x)
    Swap the point with the mark. Set the current cursor position to the saved position, then set the mark to the old cursor position.
character-search (C-])
    Read a character and move point to the next occurrence of that character. A negative argument searches for previous occurrences.
character-search-backward (M-C-])
    Read a character and move point to the previous occurrence of that character. A negative argument searches for subsequent occurrences.
skip-csi-sequence
    Read enough characters to consume a multi-key sequence such as those defined for keys like Home and End. CSI sequences begin with a Control Sequence Indicator (CSI), usually ESC [. If this sequence is bound to keys producing CSI sequences 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 [.
insert-comment (M-#)
    Without a numeric argument, insert the value of the readline comment-begin variable 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 comment-begin, insert the value; otherwise delete the characters in comment-begin from the beginning of the line. In either case, the line is accepted as if a newline had been typed. The default value of 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.
dump-functions
    Print all of the functions and their key bindings to the readline output stream. If a numeric argument is supplied, the output is formatted in such a way that it can be made part of an inputrc file.
dump-variables
    Print all of the settable variables and their values to the readline output stream. If a numeric argument is supplied, the output is formatted in such a way that it can be made part of an inputrc file.
dump-macros
    Print all of the readline key sequences bound to macros and the strings they output to the readline output stream. If a numeric argument is supplied, the output is formatted in such a way that it can be made part of an inputrc file.
execute-named-command (M-x)
    Read a bindable readline command name from the input and execute the function to which it's bound, as if the key sequence to which it was bound appeared in the input. If this function is supplied with a numeric argument, it passes that argument to the function it executes.
emacs-editing-mode (C-e)
    When in vi command mode, this switches readline to emacs editing mode.
vi-editing-mode (M-C-j)
    When in emacs editing mode, this switches to vi editing mode.

DEFAULT KEY BINDINGS

The following is a list of the default emacs and vi bindings. Characters with the eighth bit set are written as M-<character>, and are referred to as metafied characters. The printable ASCII characters not mentioned in the list of emacs standard bindings are bound to the self-insert function, which just inserts the given character into the input line. In vi insertion mode, all characters not specifically mentioned are bound to self-insert. Characters assigned to signal generation by stty(1) or the terminal driver, such as C-Z or C-C, retain that function. Upper and lower case metafied characters are bound to the same function in the emacs mode meta keymap. The remaining characters are unbound, which causes readline to ring the bell (subject to the setting of the bell-style variable).

  Emacs Mode

    Emacs Standard bindings

    "C-@"  set-mark
    "C-A"  beginning-of-line
    "C-B"  backward-char
    "C-D"  delete-char
    "C-E"  end-of-line
    "C-F"  forward-char
    "C-G"  abort
    "C-H"  backward-delete-char
    "C-I"  complete
    "C-J"  accept-line
    "C-K"  kill-line
    "C-L"  clear-screen
    "C-M"  accept-line
    "C-N"  next-history
    "C-P"  previous-history
    "C-Q"  quoted-insert
    "C-R"  reverse-search-history
    "C-S"  forward-search-history
    "C-T"  transpose-chars
    "C-U"  unix-line-discard
    "C-V"  quoted-insert
    "C-W"  unix-word-rubout
    "C-Y"  yank
    "C-]"  character-search
    "C-_"  undo
    " " to "/"  self-insert
    "0"  to "9"  self-insert
    ":"  to "~"  self-insert
    "C-?"  backward-delete-char

    Emacs Meta bindings

    "M-C-G"  abort
    "M-C-H"  backward-kill-word
    "M-C-I"  tab-insert
    "M-C-J"  vi-editing-mode
    "M-C-L"  clear-display
    "M-C-M"  vi-editing-mode
    "M-C-R"  revert-line
    "M-C-Y"  yank-nth-arg
    "M-C-["  complete
    "M-C-]"  character-search-backward
    "M-space"  set-mark
    "M-#"  insert-comment
    "M-&"  tilde-expand
    "M-*"  insert-completions
    "M--"  digit-argument
    "M-."  yank-last-arg
    "M-0"  digit-argument
    "M-1"  digit-argument
    "M-2"  digit-argument
    "M-3"  digit-argument
    "M-4"  digit-argument
    "M-5"  digit-argument
    "M-6"  digit-argument
    "M-7"  digit-argument
    "M-8"  digit-argument
    "M-9"  digit-argument
    "M-<"  beginning-of-history
    "M-="  possible-completions
    "M->"  end-of-history
    "M-?"  possible-completions
    "M-B"  backward-word
    "M-C"  capitalize-word
    "M-D"  kill-word
    "M-F"  forward-word
    "M-L"  downcase-word
    "M-N"  non-incremental-forward-search-history
    "M-P"  non-incremental-reverse-search-history
    "M-R"  revert-line
    "M-T"  transpose-words
    "M-U"  upcase-word
    "M-X"  execute-named-command
    "M-Y"  yank-pop
    "M-\"  delete-horizontal-space
    "M-~"  tilde-expand
    "M-C-?"  backward-kill-word
    "M-_"  yank-last-arg

    Emacs Control-X bindings

    "C-XC-G"  abort
    "C-XC-R"  re-read-init-file
    "C-XC-U"  undo
    "C-XC-X"  exchange-point-and-mark
    "C-X("  start-kbd-macro
    "C-X)"  end-kbd-macro
    "C-XE"  call-last-kbd-macro
    "C-XC-?"  backward-kill-line

  VI Mode bindings

    VI Insert Mode functions

    "C-D"  vi-eof-maybe
    "C-H"  backward-delete-char
    "C-I"  complete
    "C-J"  accept-line
    "C-M"  accept-line
    "C-N"  menu-complete
    "C-P"  menu-complete-backward
    "C-R"  reverse-search-history
    "C-S"  forward-search-history
    "C-T"  transpose-chars
    "C-U"  unix-line-discard
    "C-V"  quoted-insert
    "C-W"  vi-unix-word-rubout
    "C-Y"  yank
    "C-["  vi-movement-mode
    "C-_"  vi-undo
    " " to "~"  self-insert
    "C-?"  backward-delete-char

    VI Command Mode functions

    "C-D"  vi-eof-maybe
    "C-E"  emacs-editing-mode
    "C-G"  abort
    "C-H"  backward-char
    "C-J"  accept-line
    "C-K"  kill-line
    "C-L"  clear-screen
    "C-M"  accept-line
    "C-N"  next-history
    "C-P"  previous-history
    "C-Q"  quoted-insert
    "C-R"  reverse-search-history
    "C-S"  forward-search-history
    "C-T"  transpose-chars
    "C-U"  unix-line-discard
    "C-V"  quoted-insert
    "C-W"  vi-unix-word-rubout
    "C-Y"  yank
    "C-_"  vi-undo
    " "  forward-char
    "#"  insert-comment
    "$"  end-of-line
    "%"  vi-match
    "&"  vi-tilde-expand
    "*"  vi-complete
    "+"  next-history
    ","  vi-char-search
    "-"  previous-history
    "."  vi-redo
    "/"  vi-search
    "0"  beginning-of-line
    "1" to "9"  vi-arg-digit
    ";"  vi-char-search
    "="  vi-complete
    "?"  vi-search
    "A"  vi-append-eol
    "B"  vi-prev-word
    "C"  vi-change-to
    "D"  vi-delete-to
    "E"  vi-end-word
    "F"  vi-char-search
    "G"  vi-fetch-history
    "I"  vi-insert-beg
    "N"  vi-search-again
    "P"  vi-put
    "R"  vi-replace
    "S"  vi-subst
    "T"  vi-char-search
    "U"  revert-line
    "W"  vi-next-word
    "X"  vi-rubout
    "Y"  vi-yank-to
    "\"  vi-complete
    "^"  vi-first-print
    "_"  vi-yank-arg
    "`"  vi-goto-mark
    "a"  vi-append-mode
    "b"  vi-prev-word
    "c"  vi-change-to
    "d"  vi-delete-to
    "e"  vi-end-word
    "f"  vi-char-search
    "h"  backward-char
    "i"  vi-insertion-mode
    "j"  next-history
    "k"  previous-history
    "l"  forward-char
    "m"  vi-set-mark
    "n"  vi-search-again
    "p"  vi-put
    "r"  vi-change-char
    "s"  vi-subst
    "t"  vi-char-search
    "u"  vi-undo
    "w"  vi-next-word
    "x"  vi-delete
    "y"  vi-yank-to
    "|"  vi-column
    "~"  vi-change-case

SEE ALSO
The Gnu Readline Library, Brian Fox and Chet Ramey
The Gnu History Library, Brian Fox and Chet Ramey
bash(1)

FILES
Individual readline initialization file

AUTHORS
Brian Fox, Free Software Foundation
bfox@gnu.org

Chet Ramey, Case Western Reserve University
chet.ramey@case.edu

BUG REPORTS
If you find a bug in readline, you should report it. But first, you should make sure that it really is a bug, and that it appears in the latest version of the readline library that you have.

Once you have determined that a bug actually exists, mail a bug report to bug-readline@gnu.org. If you have a fix, you are welcome to mail that as well! Suggestions and bug reports may be mailed to bug-readline@gnu.org or posted to the Usenet newsgroup gnu.bash.bug.

Comments and bug reports concerning this manual page should be directed to chet.ramey@case.edu.

BUGS
It's too big and too slow.