readline/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:

       active-region-start-color
              A string variable that controls the text  color  and  background
              when  displaying the text in the active region (see the descrip-
              tion of enable-active-region below).  This string must not  take
              up any physical character positions on the display, so it should
              consist only of terminal escape sequences.  It is output to  the
              terminal  before displaying the text in the active region.  This
              variable is reset to the default  value  whenever  the  terminal
              type  changes.   The  default  value is the string that puts the
              terminal in standout mode, as obtained from the terminal's  ter-
              minfo description.  A sample value might be "\e[01;33m".
       active-region-end-color
              A  string  variable  that  "undoes"  the  effects  of active-re-
              gion-start-color and restores "normal" terminal display  appear-
              ance  after  displaying  text in the active region.  This string
              must not take up any physical character positions  on  the  dis-
              play,  so  it  should consist only of terminal escape sequences.
              It is output to the terminal after displaying the  text  in  the
              active  region.   This  variable  is  reset to the default value
              whenever the terminal type changes.  The default  value  is  the
              string  that  restores  the  terminal from standout mode, as ob-
              tained from the terminal's terminfo description.  A sample value
              might be "\e[0m".
       bell-style (audible)
              Controls  what  happens when readline wants to ring the terminal
              bell.  If set to none, readline never rings the bell.  If set to
              visible,  readline  uses a visible bell if one is available.  If
              set to audible, readline attempts to ring the terminal's bell.
       bind-tty-special-chars (On)
              If set to On (the default), readline attempts to bind  the  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.  If there is a color defini-
              tion  in $LS_COLORS for the custom suffix "readline-colored-com-
              pletion-prefix", readline uses this color for the common  prefix
              instead of its default.
       colored-stats (Off)
              If  set to On, readline displays possible completions using 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.   This
              variable  is  dependent on the LC_CTYPE locale category, and may
              change if the locale is changed.
       disable-completion (Off)
              If set to On, readline will inhibit word completion.  Completion
              characters  will  be  inserted into the line as if they had been
              mapped to self-insert.
       echo-control-characters (On)
              When set to On, on operating systems that indicate they  support
              it, readline echoes a character corresponding to a signal 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-active-region (On)
              The  point  is the current cursor position, and mark refers to a
              saved cursor position.  The text between the point and  mark  is
              referred  to  as  the  region.  When this variable is set to On,
              readline allows certain commands to designate the region as  ac-
              tive.   When  the region is active, readline highlights the text
              in the region using the value of the  active-region-start-color,
              which  defaults to the string that enables the terminal's stand-
              out mode.  The active region shows the text inserted  by  brack-
              eted-paste  and  any matching text found by incremental and non-
              incremental history searches.
       enable-bracketed-paste (On)
              When set to On, readline configures the terminal to insert  each
              paste  into the editing buffer as a single string of characters,
              instead of treating each character as if it had been  read  from
              the keyboard.  This prevents readline from executing any editing
              commands bound to key sequences appearing in the pasted text.
       enable-keypad (Off)
              When set to On, readline will try to enable the application 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.  This variable is dependent on the  LC_CTYPE  locale
              category, and may change if the locale is changed.
       isearch-terminators (``C-[ C-J'')
              The  string  of  characters that should terminate an incremental
              search without subsequently executing the character  as  a  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.  This variable  is  dependent  on
              the  LC_CTYPE  locale  category, and may change if the locale is
              changed.
       page-completions (On)
              If set to On, readline uses an internal more-like pager to  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.
       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.
       fetch-history
              With a numeric argument, fetch that entry from the history  list
              and make it the current line.  Without an argument, move back to
              the first entry in the history list.
       reverse-search-history (C-r)
              Search backward starting at the current  line  and  moving  `up'
              through  the  history  as  necessary.   This  is  an incremental
              search.
       forward-search-history (C-s)
              Search forward starting at the current line  and  moving  `down'
              through  the  history  as  necessary.   This  is  an incremental
              search.
       non-incremental-reverse-search-history (M-p)
              Search backward through the history starting at the current line
              using  a  non-incremental  search  for  a string supplied by the
              user.
       non-incremental-forward-search-history (M-n)
              Search forward  through  the  history  using  a  non-incremental
              search for a string supplied by the user.
       history-search-backward
              Search backward through the history for the string of characters
              between the start of the current line and the current cursor 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.

   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 argument searches for  previous  oc-
              currences.
       character-search-backward (M-C-])
              A  character  is  read and point is moved to the previous occur-
              rence of that character.  A negative argument searches for  sub-
              sequent 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 8.2               2022 September 19                   READLINE(3)