READLINE(3) - phpMan

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);

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 in-
formation.

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-Con-
trol-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 nega-
tive 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 devi-
ates 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 li-
brary 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 ig-
nored. Lines beginning with a # are comments. Lines beginning with a $ indicate condi-
tional 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 in-
serted when the key is pressed (a macro).

Key Bindings
The syntax for controlling key bindings in the inputrc file is simple. All that is re-
quired 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:

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 termi-
nal'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 parenthe-
sis 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.
colored-stats (Off)
If set to On, readline displays possible completions using different colors to in-
dicate 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 com-
pletion. 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-insensi-
tive 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 match-
ing 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 display-
ing possible completions.
completion-query-items (100)
This determines when the user is queried about viewing the number of possible com-
pletions generated by the possible-completions command. It may be set to any inte-
ger 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.
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 immedi-
ately 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-bracketed-paste (On)
When set to On, readline will configure the terminal in a way that will enable it
to insert each paste into the editing buffer as a single string of characters, in-
stead of treating each character as if it had been read from the keyboard. This
can prevent pasted characters from being interpreted as editing commands.
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 ter-
minals 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.
isearch-terminators (``C-[ C-J'')
The string of characters that should terminate an incremental search without subse-
quently 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 se-
quence. 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 un-
til 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.
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 in-
dividual 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 immedi-
ately 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 ring-
ing 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 immedi-
ately 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 immedi-
ately 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 termi-
nal 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 com-
mand, 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, per-
haps 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 ter-
minal 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 read-
line 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 ma-
jor 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 num-
ber 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 in-
stance, 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 vari-
ables 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 bind-
ings 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 par-
ticular string, type C-r. Typing C-s searches forward through the history. The charac-
ters present in the value of the isearch-terminators variable are used to terminate an in-
cremental search. If that variable has not been assigned a value the Escape and C-J char-
acters will terminate an incremental search. C-G will abort an incremental search and re-
store 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 com-
mand will terminate the search, make the last line found the current line, and begin edit-
ing.

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 con-
tents 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 char-
acters (letters and digits).
backward-word (M-b)
Move back to the start of the current or previous word. Words are composed of al-
phanumeric 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 Read-
line 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.
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-incre-
mental 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 sup-
plied 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 his-
tory 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 spec-
ified.
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. Suc-
cessive 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 di-
rection 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.
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.

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 be-
ginning 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 back-
ward-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 re-
ferred 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 argu-
ment. 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 argu-
ment 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 per-
formed 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 at-
tempted. Gdb, on the other hand, allows completion of program functions and vari-
ables, and only attempts filename completion under certain circumstances.
possible-completions (M-?)
List the possible completions of the text before point. When displaying comple-
tions, readline sets the number of columns used for display to the value of comple-
tion-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 comple-
tions, as if menu-complete had been given a negative argument. This command is un-
bound 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 def-
inition.
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 set-
ting 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 cor-
responding 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 po-
sition, and the old cursor position is saved as the mark.
character-search (C-])
A character is read and point is moved to the next occurrence of that character. A
negative count searches for previous occurrences.
character-search-backward (M-C-])
A character is read and point is moved to the previous occurrence of that charac-
ter. A negative count 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 se-
quences 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 in-
serted 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 charac-
ters 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 com-
ment-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 out-
put. 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 AT gnu.org

Chet Ramey, Case Western Reserve University
chet.ramey AT 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-read-
line AT 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 AT 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 AT case.edu.

BUGS
It's too big and too slow.

GNU Readline 8.1 2020 October 29 READLINE(3)

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