path: root/doc/readline.0

READLINE(3)                Library Functions Manual                READLINE(3)



NAME
       readline - get a line from a user with editing

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

       char *
       readline (const char *prompt);

COPYRIGHT
       Readline is Copyright (C) 1989-2020 Free Software Foundation,  Inc.

DESCRIPTION
       readline will read a line from the terminal and return it, using prompt
       as a prompt.  If prompt is NULL or the empty string, no prompt  is  is-
       sued.   The  line returned is allocated with malloc(3); the caller must
       free it when finished.  The line returned has  the  final  newline  re-
       moved, so only the text of the line remains.

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

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

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

NOTATION
       An Emacs-style notation is used to denote keystrokes.  Control keys are
       denoted  by C-key, e.g., C-n means Control-N.  Similarly, meta keys are
       denoted by M-key, so M-x means Meta-X.  (On keyboards  without  a  meta
       key,  M-x means ESC x, i.e., press the Escape key then the x key.  This
       makes ESC the meta prefix.  The combination M-C-x means  ESC-Control-x,
       or  press the Escape key then hold the Control key while pressing the x
       key.)

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

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

INITIALIZATION FILE
       Readline  is  customized  by putting commands in an initialization file
       (the inputrc file).  The name of this file is taken from the  value  of
       the  INPUTRC  environment variable.  If that variable is unset, the de-
       fault is ~/.inputrc.  If that file  does not exist or cannot  be  read,
       the  ultimate  default  is /etc/inputrc.  When a program which uses the
       readline library starts up, the init file is read, and the key bindings
       and  variables  are set.  There are only a few basic constructs allowed
       in the readline init file.  Blank lines are ignored.   Lines  beginning
       with  a  # are comments.  Lines beginning with a $ indicate conditional
       constructs.  Other lines denote key  bindings  and  variable  settings.
       Each program using this library may add its own commands and bindings.

       For example, placing

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

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

       The following symbolic character names are recognized while  processing
       key  bindings:  DEL,  ESC,  ESCAPE,  LFD, NEWLINE, RET, RETURN, RUBOUT,
       SPACE, SPC, and TAB.

       In addition to command names, readline allows keys to  be  bound  to  a
       string that is inserted when the key is pressed (a macro).

   Key Bindings
       The  syntax for controlling key bindings in the inputrc file is simple.
       All that is required is the name of the command or the text of a  macro
       and a key sequence to which it should be bound.  The name may be speci-
       fied 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 speci-
       fying 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 modi-
       fied with the bind builtin command.  The editing mode may  be  switched
       during  interactive  use by using the -o option to the set builtin com-
       mand.  Other programs using this library  provide  similar  mechanisms.
       The  inputrc  file may be edited and re-read if a program does not pro-
       vide any other means to incorporate new bindings.

   Variables
       Readline has variables that can be used to further customize its behav-
       ior.  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-insen-
       sitive), 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 (the default), readline attempts to bind the con-
              trol 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 differ-
              ent 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 dif-
              ferent colors to indicate their file type.   The  color  defini-
              tions  are  taken  from  the  value of the LS_COLORS environment
              variable.
       comment-begin (``#'')
              The string that is inserted in vi mode when  the  insert-comment
              command is executed.  This command is bound to M-# in emacs mode
              and to # in vi command mode.
       completion-display-width (-1)
              The number of screen columns used to  display  possible  matches
              when  performing completion.  The value is ignored if it is less
              than 0 or greater than the terminal screen width.  A value of  0
              will  cause  matches  to be displayed one per line.  The default
              value is -1.
       completion-ignore-case (Off)
              If set to On, readline performs filename matching and completion
              in a case-insensitive fashion.
       completion-map-case (Off)
              If  set  to  On, and completion-ignore-case is enabled, readline
              treats hyphens (-) and underscores (_) as equivalent  when  per-
              forming case-insensitive filename matching and completion.
       completion-prefix-display-length (0)
              The  length in characters of the common prefix of a list of pos-
              sible 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  possi-
              ble completions.
       completion-query-items (100)
              This  determines when the user is queried about viewing the num-
              ber of possible completions generated  by  the  possible-comple-
              tions  command.  It may be set to any integer value greater than
              or equal to zero.  If the  number  of  possible  completions  is
              greater  than  or  equal to the value of this variable, readline
              will ask whether or not the user wishes to view them;  otherwise
              they are simply listed on the terminal.  A negative value causes
              readline to never ask.
       convert-meta (On)
              If set to On, readline will convert characters with  the  eighth
              bit set to an ASCII key sequence by stripping the eighth bit and
              prefixing it with an escape character (in effect,  using  escape
              as  the  meta prefix).  The default is On, but readline will set
              it to Off if the locale contains eight-bit characters.
       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 gener-
              ated from the keyboard.
       editing-mode (emacs)
              Controls whether readline begins with a set of key bindings sim-
              ilar 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 char-
              acter as if it had been read from the keyboard.  This  can  pre-
              vent  pasted  characters  from being interpreted as editing com-
              mands.
       enable-keypad (Off)
              When set to On, readline will try to enable the application key-
              pad when it is called.  Some systems need this to enable the ar-
              row 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  at-
              tempts 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-his-
              tory or next-history.
       history-size (unset)
              Set  the  maximum number of history entries saved in the history
              list.  If set to zero, any existing history entries are  deleted
              and no new entries are saved.  If set to a value less than zero,
              the number of history entries is not limited.  By  default,  the
              number of history entries is not limited.  If an attempt is made
              to set history-size to a non-numeric value, the  maximum  number
              of history entries will be set to 500.
       horizontal-scroll-mode (Off)
              When  set  to  On, makes readline use a single line for display,
              scrolling the input horizontally on a single screen line when it
              becomes  longer  than the screen width rather than wrapping to a
              new line.  This setting is automatically enabled  for  terminals
              of height 1.
       input-meta (Off)
              If  set to On, readline will enable eight-bit input (that is, it
              will not clear the eighth bit in the characters it  reads),  re-
              gardless  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 com-
              mand.  If this variable has not been given a value, the  charac-
              ters 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 re-
              ceived 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  dis-
              played with a preceding asterisk (*).
       mark-symlinked-directories (Off)
              If set to On, completed names which are symbolic links to direc-
              tories have a slash appended (subject to the value  of  mark-di-
              rectories).
       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 dis-
              play 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, his-
              tory 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  possi-
              ble  partial  completion (the possible completions don't share a
              common prefix) cause the matches to be  listed  immediately  in-
              stead of ringing the bell.
       show-mode-in-prompt (Off)
              If  set to On, add a string to the beginning of the prompt indi-
              cating 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  con-
              trol 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 con-
              trol 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 com-
              pletions.

   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 edit-
              ing 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 char-
              acters 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 in-
                     stance, to set bindings in the emacs-standard and  emacs-
                     ctlx  keymaps  only  if readline is starting out in emacs
                     mode.

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

              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  op-
                     erator  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  li-
                     brary  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 vari-
                     ables 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  follow-
              ing 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,  read-
       line displays the next entry from the history matching the string typed
       so far.  An incremental search requires  only  as  many  characters  as
       needed  to  find  the desired history entry.  To search backward in the
       history for a particular string, type C-r.  Typing C-s searches forward
       through  the  history.   The  characters  present  in  the value of the
       isearch-terminators variable  are  used  to  terminate  an  incremental
       search.   If that variable has not been assigned a value the Escape and
       C-J characters will terminate an incremental search.  C-G will abort an
       incremental  search  and restore the original line.  When the search is
       terminated, the history entry containing the search string becomes  the
       current line.

       To  find other matching entries in the history list, type C-s or C-r as
       appropriate.  This will search backward or forward in the  history  for
       the  next  line matching the search string typed so far.  Any other key
       sequence bound to a readline command will terminate the search and exe-
       cute  that  command.  For instance, a newline will terminate the search
       and accept the line, thereby executing the  command  from  the  history
       list.  A movement command will terminate the search, make the last line
       found the current line, and begin editing.

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

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

       In the following descriptions, point refers to the current cursor posi-
       tion,  and  mark refers to a cursor position saved by the set-mark com-
       mand.  The text between the point and mark is referred to  as  the  re-
       gion.

   Commands for Moving
       beginning-of-line (C-a)
              Move to the start of the current line.
       end-of-line (C-e)
              Move to the end of the line.
       forward-char (C-f)
              Move forward a character.
       backward-char (C-b)
              Move back a character.
       forward-word (M-f)
              Move forward to the end of the next word.  Words are composed of
              alphanumeric characters (letters and digits).
       backward-word (M-b)
              Move back to the start of the current or previous  word.   Words
              are composed of alphanumeric characters (letters and digits).
       previous-screen-line
              Attempt  to move point to the same physical screen column on the
              previous physical screen line. This will not  have  the  desired
              effect  if  the current Readline line does not take up more than
              one physical line or if point is not greater than the length  of
              the prompt plus the screen width.
       next-screen-line
              Attempt  to move point to the same physical screen column on the
              next physical screen line. This will not have the desired effect
              if  the  current  Readline  line  does not take up more than one
              physical line or if the length of the current Readline  line  is
              not greater than the length of the prompt plus the screen width.
       clear-display (M-C-l)
              Clear  the  screen  and,  if possible, the terminal's scrollback
              buffer, then redraw the current line, leaving the  current  line
              at the top of the screen.
       clear-screen (C-l)
              Clear the screen, then redraw the current line, leaving the cur-
              rent 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 re-
              call  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-incremental search for  a  string  supplied  by  the
              user.
       non-incremental-forward-search-history (M-n)
              Search  forward  through  the  history  using  a non-incremental
              search for a string supplied by the user.
       history-search-backward
              Search backward through the history for the string of characters
              between the start of the current line and the current cursor po-
              sition (the point).  The search string must match at the  begin-
              ning 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 po-
              sition (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-in-
              cremental 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 in-
              serts the nth word from the end of the previous  command.   Once
              the  argument n is computed, the argument is extracted as if the
              "!n" history expansion had been specified.
       yank-last-arg (M-., M-_)
              Insert the last argument to the previous command (the last  word
              of the previous history entry).  With a numeric argument, behave
              exactly like yank-nth-arg.  Successive  calls  to  yank-last-arg
              move  back through the history list, inserting the last word (or
              the word specified by the argument to the first  call)  of  each
              line in turn.  Any numeric argument supplied to these successive
              calls determines the direction to move through the  history.   A
              negative  argument  switches  the  direction through the history
              (back or forward).  The history expansion facilities are used to
              extract  the last argument, as if the "!$" history expansion had
              been specified.
       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 ar-
              gument,  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 charac-
              ters 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 cur-
              sor 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  ar-
              gument, uppercase the previous word, but do not move point.
       downcase-word (M-l)
              Lowercase  the current (or following) word.  With a negative ar-
              gument, lowercase the previous word, but do not move point.
       capitalize-word (M-c)
              Capitalize the current (or following) word.  With a negative ar-
              gument, capitalize the previous word, but do not move point.
       overwrite-mode
              Toggle  overwrite mode.  With an explicit positive numeric argu-
              ment, 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, charac-
              ters bound to self-insert replace the text at point rather  than
              pushing  the  text  to  the  right.   Characters  bound to back-
              ward-delete-char replace  the  character  before  point  with  a
              space.  By default, this command is unbound.

   Killing and Yanking
       kill-line (C-k)
              Kill the text from point to the end of the line.
       backward-kill-line (C-x Rubout)
              Kill backward to the beginning of the line.
       unix-line-discard (C-u)
              Kill  backward  from  point  to  the beginning of the line.  The
              killed text is saved on the kill-ring.
       kill-whole-line
              Kill all characters on the current line, no matter  where  point
              is.
       kill-word (M-d)
              Kill  from  point  the  end  of  the current word, or if between
              words, to the end of the next word.   Word  boundaries  are  the
              same as those used by forward-word.
       backward-kill-word (M-Rubout)
              Kill  the  word  behind  point.  Word boundaries are the same as
              those used by backward-word.
       unix-word-rubout (C-w)
              Kill the word behind point, using white space as a  word  bound-
              ary.  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 posi-
              tion).  This text is referred to as the region.
       copy-region-as-kill
              Copy the text in the region to the kill buffer.
       copy-backward-word
              Copy the word before point to the kill buffer.  The word  bound-
              aries 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  follow-
              ing 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  fol-
              lowed by digits, executing universal-argument again ends the nu-
              meric argument, but is otherwise ignored.  As a special case, if
              this command is immediately followed by a character that is nei-
              ther a digit or minus sign, the argument count for the next com-
              mand  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 ac-
              tual  completion  performed  is application-specific.  Bash, for
              instance, attempts completion treating the text  as  a  variable
              (if  the  text begins with $), username (if the text begins with
              ~), hostname (if the text begins with @), or command  (including
              aliases  and  functions)  in  turn.  If none of these produces a
              match, filename completion is  attempted.   Gdb,  on  the  other
              hand,  allows completion of program functions and variables, and
              only attempts filename completion under certain circumstances.
       possible-completions (M-?)
              List the possible completions of the text  before  point.   When
              displaying completions, readline sets the number of columns used
              for display to the value of completion-display-width, the  value
              of  the  environment  variable  COLUMNS, or the screen width, in
              that order.
       insert-completions (M-*)
              Insert all completions of the text before point that would  have
              been generated by possible-completions.
       menu-complete
              Similar  to complete, but replaces the word to be completed with
              a single match from the list of possible completions.   Repeated
              execution  of  menu-complete  steps through the list of possible
              completions, inserting each match in turn.  At the  end  of  the
              list of completions, the bell is rung (subject to the setting of
              bell-style) and the original text is restored.  An argument of n
              moves n positions forward in the list of matches; a negative ar-
              gument may be used to move backward through the list.  This com-
              mand is intended to be bound to TAB, but is unbound by default.
       menu-complete-backward
              Identical  to menu-complete, but moves backward through the list
              of possible completions, as if menu-complete had  been  given  a
              negative argument.  This command is unbound by default.
       delete-char-or-list
              Deletes  the  character under the cursor if not at the beginning
              or end of the line (like delete-char).  If at  the  end  of  the
              line, behaves identically to possible-completions.

   Keyboard Macros
       start-kbd-macro (C-x ()
              Begin  saving  the  characters  typed  into the current keyboard
              macro.
       end-kbd-macro (C-x ))
              Stop saving the characters typed into the current keyboard macro
              and store the definition.
       call-last-kbd-macro (C-x e)
              Re-execute  the last keyboard macro defined, by making the char-
              acters 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 occur-
              rences.
       character-search-backward (M-C-])
              A character is read and point is moved to  the  previous  occur-
              rence  of  that character.  A negative count searches for subse-
              quent 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  com-
              ment-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,  other-
              wise the characters in comment-begin are deleted from the begin-
              ning of the line.  In either case, the line is accepted as if  a
              newline  had  been  typed.   The  default value of comment-begin
              makes the current line a shell comment.  If a  numeric  argument
              causes the comment character to be removed, the line will be ex-
              ecuted by the shell.
       dump-functions
              Print all of the functions and their key bindings to  the  read-
              line output stream.  If a numeric argument is supplied, the out-
              put is formatted in such a way that it can be made  part  of  an
              inputrc file.
       dump-variables
              Print  all  of  the  settable  variables and their values to the
              readline output stream.  If a numeric argument is supplied,  the
              output is formatted in such a way that it can be made part of an
              inputrc file.
       dump-macros
              Print all of the readline key sequences bound to macros and  the
              strings  they  output.   If  a numeric argument is supplied, the
              output is formatted in such a way that it can be made part of an
              inputrc file.
       emacs-editing-mode (C-e)
              When  in  vi command mode, this causes a switch to emacs editing
              mode.
       vi-editing-mode (M-C-j)
              When in emacs editing mode, this causes a switch to  vi  editing
              mode.

DEFAULT KEY BINDINGS
       The  following is a list of the default emacs and vi bindings.  Charac-
       ters with the eighth bit set are written as M-<character>, and are  re-
       ferred  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 men-
       tioned are bound to self-insert.  Characters assigned to signal genera-
       tion by stty(1) or the terminal driver, such as C-Z or C-C, retain that
       function.   Upper  and  lower case metafied characters are bound to the
       same function in the emacs mode meta keymap.  The remaining  characters
       are  unbound,  which  causes  readline to ring the bell (subject to the
       setting of the bell-style variable).

   Emacs Mode
             Emacs Standard bindings

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

             Emacs Meta bindings

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

             Emacs Control-X bindings

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


   VI Mode bindings
             VI Insert Mode functions

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

             VI Command Mode functions

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

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

FILES
       ~/.inputrc
              Individual readline initialization file

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

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

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

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

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

BUGS
       It's too big and too slow.



GNU Readline 8.1                2020 October 29                    READLINE(3)