gNU Bourne-Again SHell (GNU Bourne-Again SHell)
READLINE
This is the library that handles reading input when using an
interactive shell, unless the --noediting option is given at
shell invocation. Line editing is also used when using the -e
option to the read builtin. By default, the line editing
commands are similar to those of Emacs. A vi-style line editing
interface is also available. Line editing can be enabled at any
time using the -o emacs or -o vi options to the set builtin (see
SHELL BUILTIN COMMANDS below). To turn off line editing after
the shell is running, use the +o emacs or +o vi options to the
set builtin.
Readline Notation
In this section, the 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.
Readline Initialization
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 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 initialization file is
read, and the key bindings and variables are set. There are only
a few basic constructs allowed in the readline initialization
file. Blank lines are ignored. Lines beginning with a # are
comments. Lines beginning with a $ indicate conditional
constructs. Other lines denote key bindings and variable
settings.
The default key-bindings may be changed with an inputrc file.
Other programs that use this library may add their own commands
and bindings.
For example, placing
M-Control-u: universal-argument
or
C-Meta-u: universal-argument
into the inputrc would make M-C-u execute the readline command
universal-argument.
The following symbolic character names are recognized: RUBOUT,
DEL, ESC, LFD, NEWLINE, RET, RETURN, SPC, SPACE, 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).
Readline 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.
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 is
\C- control prefix
\M- meta prefix
\e an escape character
\\ backslash
\" literal "
\' literal '
In addition to the GNU Emacs style escape sequences, a second set
of backslash escapes is available:
\a alert (bell)
\b backspace
\d delete
\f form feed
\n newline
\r carriage return
\t horizontal tab
\v vertical tab
\nnn the eight-bit character whose value is the octal
value nnn (one to three digits)
\xHH the eight-bit character whose value is the
hexadecimal value HH (one or two hex digits)
When entering the text of a macro, single or double quotes must
be used to indicate a macro definition. Unquoted text is assumed
to be a function name. 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 (see SHELL BUILTIN COMMANDS below).
Readline 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
or using the bind builtin command (see SHELL BUILTIN COMMANDS
below).
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 terminal's bell.
bind-tty-special-chars (On)
If set to On, 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.
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 when the readline
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.
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 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 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-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, instead
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 set to the value of the HISTSIZE shell variable. 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 strip the eighth bit from 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 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 valid keymap
names is emacs, emacs-standard, emacs-meta, emacs-ctlx,
vi, vi-command, and vi-insert. vi is equivalent to
vi-command; emacs is equivalent to emacs-standard. The
default value is emacs; the value of editing-mode also
affects the default keymap.
keyseq-timeout (500)
Specifies the duration readline will wait for a character
when reading an ambiguous key sequence (one that can form
a complete key sequence using the input read so far, or
can take additional input to complete a longer key
sequence). If 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.
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.
Readline 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 both 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 (see HISTORY below) 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. 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 Control-J
characters will terminate an incremental search. Control-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 Control-
S or Control-R as appropriate. This will search backward or
forward in the history for the next entry matching the search
string typed so far. Any other key sequence bound to a readline
command will terminate the search and execute that command. For
instance, a newline will terminate the search and accept the
line, thereby executing the command from the history list.
Readline remembers the last incremental search string. If two
Control-Rs are typed without any intervening characters defining
a new search string, any remembered search string is used.
Non-incremental searches read the entire search string before
starting to search for matching history lines. The search string
may be typed by the user or be part of the contents of the
current line.
Readline Command Names
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).
shell-forward-word
Move forward to the end of the next word. Words are
delimited by non-quoted shell metacharacters.
shell-backward-word
Move back to the start of the current or previous word.
Words are delimited by non-quoted shell metacharacters.
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, add it to the history list
according to the state of the HISTCONTROL variable. If
the line is a modified history line, then restore the
history line to its original state.
previous-history (C-p)
Fetch the previous command from the history list, moving
back in the list.
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-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-forward
Search forward through the history for the string of
characters between the start of the current line and the
point. This is a non-incremental search.
history-search-backward
Search backward through the history for the string of
characters between the start of the current line and the
point. 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 word, as if the
"!$" history expansion had been specified.
shell-expand-line (M-C-e)
Expand the line as the shell does. This performs alias
and history expansion as well as all of the shell word
expansions. See HISTORY EXPANSION below for a description
of history expansion.
history-expand-line (M-^)
Perform history expansion on the current line. See
HISTORY EXPANSION below for a description of history
expansion.
magic-space
Perform history expansion on the current line and insert a
space. See HISTORY EXPANSION below for a description of
history expansion.
alias-expand-line
Perform alias expansion on the current line. See ALIASES
above for a description of alias expansion.
history-and-alias-expand-line
Perform history and alias expansion on the current line.
insert-last-argument (M-., M-_)
A synonym for yank-last-arg.
operate-and-get-next (C-o)
Accept the current line for execution 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.
edit-and-execute-command (C-x C-e)
Invoke an editor on the current command line, and execute
the result as shell commands. Bash attempts to invoke
$VISUAL, $EDITOR, and emacs as the editor, in that order.
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 typed to the line verbatim. This
is how to insert characters like C-q, for example.
tab-insert (C-v 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 to the end of the current word, or if
between words, to the end of the next word. Word
boundaries are the same as those used by forward-word.
backward-kill-word (M-Rubout)
Kill the word behind point. Word boundaries are the same
as those used by backward-word.
shell-kill-word
Kill from point to the end of the current word, or if
between words, to the end of the next word. Word
boundaries are the same as those used by
shell-forward-word.
shell-backward-kill-word
Kill the word behind point. Word boundaries are the same
as those used by shell-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 in the current 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 nor minus sign, the argument count for the next
command is multiplied by four. The argument count is
initially one, so executing this function the first time
makes the argument count four, a second time makes the
argument count sixteen, and so on.
Completing
complete (TAB)
Attempt to perform completion on the text before point.
Bash attempts completion treating the text as a variable
(if the text begins with $), username (if the text begins
with ~), hostname (if the text begins with @), or command
(including aliases and functions) in turn. If none of
these produces a match, filename completion is attempted.
possible-completions (M-?)
List the possible completions of the text before point.
insert-completions (M-*)
Insert all completions of the text before point that would
have been generated by possible-completions.
menu-complete
Similar to complete, but replaces the word to be completed
with a single match from the list of possible completions.
Repeated execution of menu-complete steps through the list
of possible completions, inserting each match in turn. At
the end of the list of completions, the bell is rung
(subject to the setting of bell-style) and the original
text is restored. An argument of n moves n positions
forward in the list of matches; a negative argument may be
used to move backward through the list. This command is
intended to be bound to TAB, but is unbound by default.
menu-complete-backward
Identical to menu-complete, but moves backward through the
list of possible completions, as if menu-complete had been
given a negative argument. This command is unbound by
default.
delete-char-or-list
Deletes the character under the cursor if not at the
beginning or end of the line (like delete-char). If at
the end of the line, behaves identically to
possible-completions. This command is unbound by default.
complete-filename (M-/)
Attempt filename completion on the text before point.
possible-filename-completions (C-x /)
List the possible completions of the text before point,
treating it as a filename.
complete-username (M-~)
Attempt completion on the text before point, treating it
as a username.
possible-username-completions (C-x ~)
List the possible completions of the text before point,
treating it as a username.
complete-variable (M-$)
Attempt completion on the text before point, treating it
as a shell variable.
possible-variable-completions (C-x $)
List the possible completions of the text before point,
treating it as a shell variable.
complete-hostname (M-@)
Attempt completion on the text before point, treating it
as a hostname.
possible-hostname-completions (C-x @)
List the possible completions of the text before point,
treating it as a hostname.
complete-command (M-!)
Attempt completion on the text before point, treating it
as a command name. Command completion attempts to match
the text against aliases, reserved words, shell functions,
shell builtins, and finally executable filenames, in that
order.
possible-command-completions (C-x !)
List the possible completions of the text before point,
treating it as a command name.
dynamic-complete-history (M-TAB)
Attempt completion on the text before point, comparing the
text against lines from the history list for possible
completion matches.
dabbrev-expand
Attempt menu completion on the text before point,
comparing the text against lines from the history list for
possible completion matches.
complete-into-braces (M-{)
Perform filename completion and insert the list of
possible completions enclosed within braces so the list is
available to the shell (see Brace Expansion above).
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 count 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 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 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 causes this command to make the current line
a shell comment. If a numeric argument causes the comment
character to be removed, the line will be executed by the
shell.
glob-complete-word (M-g)
The word before point is treated as a pattern for pathname
expansion, with an asterisk implicitly appended. This
pattern is used to generate a list of matching filenames
for possible completions.
glob-expand-word (C-x *)
The word before point is treated as a pattern for pathname
expansion, and the list of matching filenames is inserted,
replacing the word. If a numeric argument is supplied, an
asterisk is appended before pathname expansion.
glob-list-expansions (C-x g)
The list of expansions that would have been generated by
glob-expand-word is displayed, and the line is redrawn.
If a numeric argument is supplied, an asterisk is appended
before pathname expansion.
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 readline 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.
display-shell-version (C-x C-v)
Display version information about the current instance of
bash.
Programmable Completion
When word completion is attempted for an argument to a command
for which a completion specification (a compspec) has been
defined using the complete builtin (see SHELL BUILTIN COMMANDS
below), the programmable completion facilities are invoked.
First, the command name is identified. If the command word is
the empty string (completion attempted at the beginning of an
empty line), any compspec defined with the -E option to complete
is used. If a compspec has been defined for that command, the
compspec is used to generate the list of possible completions for
the word. If the command word is a full pathname, a compspec for
the full pathname is searched for first. If no compspec is found
for the full pathname, an attempt is made to find a compspec for
the portion following the final slash. If those searches do not
result in a compspec, any compspec defined with the -D option to
complete is used as the default. If there is no default
compspec, bash attempts alias expansion on the command word as a
final resort, and attempts to find a compspec for the command
word from any successful expansion.
Once a compspec has been found, it is used to generate the list
of matching words. If a compspec is not found, the default bash
completion as described above under Completing is performed.
First, the actions specified by the compspec are used. Only
matches which are prefixed by the word being completed are
returned. When the -f or -d option is used for filename or
directory name completion, the shell variable FIGNORE is used to
filter the matches.
Any completions specified by a pathname expansion pattern to the
-G option are generated next. The words generated by the pattern
need not match the word being completed. The GLOBIGNORE shell
variable is not used to filter the matches, but the FIGNORE
variable is used.
Next, the string specified as the argument to the -W option is
considered. The string is first split using the characters in
the IFS special variable as delimiters. Shell quoting is
honored. Each word is then expanded using brace expansion, tilde
expansion, parameter and variable expansion, command
substitution, and arithmetic expansion, as described above under
EXPANSION. The results are split using the rules described above
under Word Splitting. The results of the expansion are prefix-
matched against the word being completed, and the matching words
become the possible completions.
After these matches have been generated, any shell function or
command specified with the -F and -C options is invoked. When
the command or function is invoked, the COMP_LINE, COMP_POINT,
COMP_KEY, and COMP_TYPE variables are assigned values as
described above under Shell Variables. If a shell function is
being invoked, the COMP_WORDS and COMP_CWORD variables are also
set. When the function or command is invoked, the first argument
($1) is the name of the command whose arguments are being
completed, the second argument ($2) is the word being completed,
and the third argument ($3) is the word preceding the word being
completed on the current command line. No filtering of the
generated completions against the word being completed is
performed; the function or command has complete freedom in
generating the matches.
Any function specified with -F is invoked first. The function
may use any of the shell facilities, including the compgen
builtin described below, to generate the matches. It must put
the possible completions in the COMPREPLY array variable, one per
array element.
Next, any command specified with the -C option is invoked in an
environment equivalent to command substitution. It should print
a list of completions, one per line, to the standard output.
Backslash may be used to escape a newline, if necessary.
After all of the possible completions are generated, any filter
specified with the -X option is applied to the list. The filter
is a pattern as used for pathname expansion; a & in the pattern
is replaced with the text of the word being completed. A literal
& may be escaped with a backslash; the backslash is removed
before attempting a match. Any completion that matches the
pattern will be removed from the list. A leading ! negates the
pattern; in this case any completion not matching the pattern
will be removed. If the nocasematch shell option is enabled, the
match is performed without regard to the case of alphabetic
characters.
Finally, any prefix and suffix specified with the -P and -S
options are added to each member of the completion list, and the
result is returned to the readline completion code as the list of
possible completions.
If the previously-applied actions do not generate any matches,
and the -o dirnames option was supplied to complete when the
compspec was defined, directory name completion is attempted.
If the -o plusdirs option was supplied to complete when the
compspec was defined, directory name completion is attempted and
any matches are added to the results of the other actions.
By default, if a compspec is found, whatever it generates is
returned to the completion code as the full set of possible
completions. The default bash completions are not attempted, and
the readline default of filename completion is disabled. If the
-o bashdefault option was supplied to complete when the compspec
was defined, the bash default completions are attempted if the
compspec generates no matches. If the -o default option was
supplied to complete when the compspec was defined, readline's
default completion will be performed if the compspec (and, if
attempted, the default bash completions) generate no matches.
When a compspec indicates that directory name completion is
desired, the programmable completion functions force readline to
append a slash to completed names which are symbolic links to
directories, subject to the value of the mark-directories
readline variable, regardless of the setting of the mark-
symlinked-directories readline variable.
There is some support for dynamically modifying completions.
This is most useful when used in combination with a default
completion specified with complete -D. It's possible for shell
functions executed as completion handlers to indicate that
completion should be retried by returning an exit status of 124.
If a shell function returns 124, and changes the compspec
associated with the command on which completion is being
attempted (supplied as the first argument when the function is
executed), programmable completion restarts from the beginning,
with an attempt to find a new compspec for that command. This
allows a set of completions to be built dynamically as completion
is attempted, rather than being loaded all at once.
For instance, assuming that there is a library of compspecs, each
kept in a file corresponding to the name of the command, the
following default completion function would load completions
dynamically:
_completion_loader()
{
. "/etc/bash_completion.d/$1.sh" >/dev/null 2>&1 && return
124
}
complete -D -F _completion_loader -o bashdefault -o default
