readline(3) Library Functions Manual 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) 1989-2020 Free Software Foundation, Inc.
DESCRIPTION
readline will read a line from the terminal and return it, using prompt
as a prompt. If prompt is NULL or the empty string, no prompt is issued.
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.
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, NULL is returned. If an EOF is read with a non-empty line, it
is treated as a newline.
NOTATION
An Emacs-style notation is used to denote 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. (On keyboards without a meta key,
M-x means ESC x, i.e., press the Escape key then the x key. This makes
ESC the meta prefix. The combination M-C-x means ESC-Control-x, or press
the Escape key then hold the Control key while pressing the x key.)
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) causes that command to act in a
backward direction. Commands whose behavior with arguments deviates from
this are noted below.
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 cause the text to be accumulated 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, the ultimate
default is /etc/inputrc. When a program which uses the readline library
starts up, the init file is read, and the key bindings and variables are
set. There are only a few basic constructs allowed in the readline init
file. Blank lines are ignored. Lines beginning with a # are comments.
Lines beginning with a $ indicate conditional constructs. Other lines
denote key bindings and variable settings. Each program using this
library may add its 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.
The following symbolic character names are recognized while processing
key bindings: DEL, ESC, ESCAPE, LFD, NEWLINE, RET, RETURN, RUBOUT, 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).
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 name may be
specified in one of two ways: as a symbolic key name, possibly with Meta-
or Control- prefixes, or as a key sequence. The name and key sequence
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 ``> output'' 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 the
symbolic character names are not 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 ``Function Key 1''.
The full set of GNU Emacs style escape sequences available when
specifying key sequences is
\C- control prefix
\M- 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 should be used
to indicate a macro definition. Unquoted text is assumed to be a
function name. In the macro body, the backslash escapes described above
are expanded. Backslash will quote any other character in the macro
text, including " and '.
Bash allows the current readline key bindings to be displayed or modified
with the bind builtin command. The editing mode may be switched during
interactive use by using the -o option to the set builtin command. Other
programs using this library provide similar mechanisms. The inputrc file
may be edited and re-read 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
a variable value is read, empty or null values, "on" (case-insensitive),
and "1" 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 "\e[01;33m".
active-region-end-color
A string variable that "undoes" the effects of
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
"\e[0m".
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 (the default), readline attempts to bind the control
characters treated specially by the kernel's terminal driver to
their readline equivalents.
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-colored-completion-
prefix", 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 is inserted in vi mode when the insert-comment
command is executed. 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 will
cause 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 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.
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 will ask whether or
not the user wishes to view them; otherwise they are simply listed
on the terminal. A negative value causes readline to never ask.
convert-meta (On)
If set to On, readline will convert characters with the eighth bit
set to an ASCII key sequence by stripping the eighth bit and
prefixing it with an escape character (in effect, using escape as
the meta prefix). The default is On, but readline will set it to
Off if the locale contains eight-bit characters. This variable is
dependent on the LC_CTYPE locale category, and may change if the
locale is changed.
disable-completion (Off)
If set to On, readline will inhibit word completion. Completion
characters will be inserted into the line as if they had been
mapped to self-insert.
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 begins with 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. Use the \1 and \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.
enable-active-region (On)
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 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,
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 prevents readline from executing any editing
commands bound to key sequences appearing in the pasted text.
enable-keypad (Off)
When set to On, readline will try to enable the application keypad
when it is called. Some systems need this to enable the arrow
keys.
enable-meta-key (On)
When set to 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.
expand-tilde (Off)
If set to On, tilde expansion is performed when readline attempts
word completion.
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. If an attempt is made
to set history-size to a non-numeric value, the maximum number of
history entries will be set to 500.
horizontal-scroll-mode (Off)
When set 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 will enable eight-bit input (that is, it
will not clear the eighth bit in the characters it reads),
regardless of what the terminal claims it can support. The name
meta-flag is a synonym for this variable. The default is Off, but
readline will set it to On if the locale contains eight-bit
characters. This variable is dependent on the LC_CTYPE locale
category, and may change if the locale is changed.
isearch-terminators (``C-[ C-J'')
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 will terminate an incremental search.
keymap (emacs)
Set the current readline keymap. The set of legal keymap names is
emacs, emacs-standard, emacs-meta, emacs-ctlx, vi, vi-move, 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 no input is received
within the timeout, readline will use 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 will wait 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, history lines that have been modified are displayed
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, causes readline to match files
whose names begin with a `.' (hidden files) when performing
filename completion. If set to Off, the leading `.' must be
supplied by the user 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 will display characters with the eighth bit
set directly rather than as a meta-prefixed escape sequence. The
default is Off, but readline will set it to On if the locale
contains eight-bit characters. This variable is dependent on the
LC_CTYPE locale category, and may change if the locale is changed.
page-completions (On)
If set to On, readline uses an internal more-like pager to display
a screenful of possible completions at a time.
print-completions-horizontally (Off)
If set to On, readline will display 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 accept-line is executed. By default,
history lines may be modified and retain individual undo lists
across calls to readline.
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. Use
the \1 and \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.
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. Use
the \1 and \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.
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 used.
$if The $if construct allows bindings to be made based on the editing
mode, the terminal being used, or the application using readline.
The text of the test, 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 the full name of the terminal and
the portion of the terminal name before the first -. This
allows sun to match both sun and sun-cmd, for instance.
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 is assumed to be 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. Both string and boolean variables may
be tested. Boolean variables must be tested against the
values on and off.
$endif This command, as seen in the previous example, terminates an $if
command.
$else Commands in this branch of the $if directive are executed if the
test fails.
$include
This directive takes a single filename as an argument and reads
commands and bindings from that file. 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. To search backward in the history for a
particular string, type C-r. Typing C-s searches forward through the
history. The characters present in the value of the isearch-terminators
variable are used to terminate an incremental search. If that variable
has not been assigned a value the Escape and C-J characters will
terminate an incremental search. C-G will abort an incremental search
and restore the original line. When the search is terminated, the
history entry containing the search string becomes the current line.
To find other matching entries in the history list, type C-s or C-r as
appropriate. This will search backward or forward in the history for the
next line 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 newline 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.
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.
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.
Commands for Moving
beginning-of-line (C-a)
Move to the start of the current line.
end-of-line (C-e)
Move to the end of the line.
forward-char (C-f)
Move forward a character.
backward-char (C-b)
Move back a character.
forward-word (M-f)
Move forward to the end of the next word. Words are composed of
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 an 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, the history line is restored to its original state.
previous-history (C-p)
Fetch the previous command from the history list, moving back in
the list.
next-history (C-n)
Fetch the next command from the history list, moving forward in
the list.
beginning-of-history (M-<)
Move to the first line in the history.
end-of-history (M->)
Move to the end of the input history, i.e., the line currently
being entered.
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 `up'
through the history as necessary. This is an incremental search.
forward-search-history (C-s)
Search forward starting at the current line and moving `down'
through the history as necessary. This is an incremental search.
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.
non-incremental-forward-search-history (M-n)
Search forward through the history using a non-incremental search
for a string supplied by the user.
history-search-backward
Search backward through the history for the string of characters
between the start of the current line and the current cursor
position (the point). The search string must match at the
beginning of a history line. This is a non-incremental search.
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.
history-substring-search-backward
Search backward through the history for the string of characters
between the start of the current line and the current cursor
position (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, the argument is extracted as if the "!n"
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). The history expansion facilities are used to extract
the last argument, 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''. 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.
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 that you type 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.
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
over 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.
Killing and Yanking
kill-line (C-k)
Kill the text from point to the end of the line.
backward-kill-line (C-x Rubout)
Kill backward to the beginning of the line.
unix-line-discard (C-u)
Kill backward from point to the beginning of the line. The killed
text is saved 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 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.
The killed text is saved on the kill-ring.
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.
delete-horizontal-space (M-\)
Delete all spaces and tabs around point.
kill-region
Kill the text between the point and mark (saved cursor position).
This text is referred to as the region.
copy-region-as-kill
Copy the text in the region to the kill buffer.
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 or minus sign, the argument count for the next
command is multiplied by four. The argument count is initially
one, so executing this function the first time makes the argument
count four, a second time makes the argument count sixteen, and so
on.
Completing
complete (TAB)
Attempt to perform completion on the text before point. The
actual completion performed is application-specific. Bash, for
instance, attempts completion 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 and functions) in turn. If none of these produces a
match, filename completion is attempted. Gdb, on the other hand,
allows completion of program functions and variables, and only
attempts filename completion under certain circumstances.
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.
menu-complete
Similar to complete, but replaces the word to be completed with a
single match from the list of possible completions. Repeated
execution of menu-complete steps through the list of possible
completions, inserting each match in turn. At the end of the list
of completions, the bell is rung (subject to the setting of
bell-style) and the original text is restored. An argument of n
moves n positions forward in the list of matches; a negative
argument may be used to move backward through the list. This
command is intended to be bound to TAB, but is unbound by default.
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.
delete-char-or-list
Deletes the character under the cursor if not at the beginning or
end of the line (like delete-char). If at the end of the line,
behaves identically to possible-completions.
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, the
mark is set to that position.
exchange-point-and-mark (C-x C-x)
Swap the point with the mark. The current cursor position is set
to the saved position, and the old cursor position is saved as the
mark.
character-search (C-])
A character is read and point is moved to the next occurrence of
that character. A negative argument searches for previous
occurrences.
character-search-backward (M-C-])
A character is read and point is moved to the previous occurrence
of that character. A negative 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. Such sequences begin
with a Control Sequence Indicator (CSI), usually ESC-[. If this
sequence is bound to "\[", 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-[.
insert-comment (M-#)
Without a numeric argument, the value of the readline
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 comment-begin, the value is inserted, otherwise
the characters in comment-begin are deleted 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 makes 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. If a numeric argument is supplied, the
output is formatted in such a way that it can be made part of an
inputrc file.
emacs-editing-mode (C-e)
When in vi command mode, this causes a switch to emacs editing
mode.
vi-editing-mode (M-C-j)
When in emacs editing mode, this causes a switch 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-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-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-[" vi-movement-mode
"C-_" 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" 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" backward-delete-char
"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" prev-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
~/.inputrc
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 `philosophical' 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.
GNU Readline 8.2 2022 September 19 readline(3)
readline 8.2.001 - Generated Thu Feb 23 07:15:08 CST 2023