(readline.info.gz) Readline Init File Syntax
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(readline.info.gz) Readline Init File
(readline.info.gz) Conditional Init Constructs
1.3.1 Readline Init File Syntax
-------------------------------
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
( Conditional Init Constructs). Other lines denote variable
settings and key bindings.
Variable Settings
You can modify the run-time behavior of Readline by altering the
values of variables in Readline using the `set' command within the
init file. The syntax is simple:
set VARIABLE VALUE
Here, for example, is how to change from the default Emacs-like
key binding to use `vi' line editing commands:
set editing-mode vi
Variable names and values, where appropriate, are recognized
without regard to case. Unrecognized variable names are ignored.
Boolean variables (those that can be set to on or off) are set to
on if the value is null or empty, ON (case-insensitive), or 1.
Any other value results in the variable being set to off.
A great deal of run-time behavior is changeable with the following
variables.
`bell-style'
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' (the default),
Readline attempts to ring the terminal's bell.
`bind-tty-special-chars'
If set to `on', Readline attempts to bind the control
characters treated specially by the kernel's terminal driver
to their Readline equivalents.
`comment-begin'
The string to insert at the beginning of the line when the
`insert-comment' command is executed. The default value is
`"#"'.
`completion-ignore-case'
If set to `on', Readline performs filename matching and
completion in a case-insensitive fashion. The default value
is `off'.
`completion-query-items'
The number of possible completions that determines when the
user is asked whether the list of possibilities should be
displayed. If the number of possible completions is greater
than this value, Readline will ask the user whether or not he
wishes to view them; otherwise, they are simply listed. This
variable must be set to an integer value greater than or
equal to 0. A negative value means Readline should never ask.
The default limit is `100'.
`convert-meta'
If set to `on', Readline will convert characters with the
eighth bit set to an ASCII key sequence by stripping the
eighth bit and prefixing an <ESC> character, converting them
to a meta-prefixed key sequence. The default value is `on'.
`disable-completion'
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'. The default is `off'.
`editing-mode'
The `editing-mode' variable controls which default set of key
bindings is used. By default, Readline starts up in Emacs
editing mode, where the keystrokes are most similar to Emacs.
This variable can be set to either `emacs' or `vi'.
`enable-keypad'
When set to `on', Readline will try to enable the application
keypad when it is called. Some systems need this to enable
the arrow keys. The default is `off'.
`expand-tilde'
If set to `on', tilde expansion is performed when Readline
attempts word completion. The default is `off'.
`history-preserve-point'
If set to `on', the history code attempts to place point at
the same location on each history line retrieved with
`previous-history' or `next-history'. The default is `off'.
`horizontal-scroll-mode'
This variable can be set to either `on' or `off'. Setting it
to `on' means that the text of the lines being edited will
scroll horizontally on a single screen line when they are
longer than the width of the screen, instead of wrapping onto
a new screen line. By default, this variable is set to `off'.
`input-meta'
If set to `on', Readline will enable eight-bit input (it will
not clear the eighth bit in the characters it reads),
regardless of what the terminal claims it can support. The
default value is `off'. The name `meta-flag' is a synonym
for this variable.
`isearch-terminators'
The string of characters that should terminate an incremental
search without subsequently executing the character as a
command ( Searching). If this variable has not been
given a value, the characters <ESC> and `C-J' will terminate
an incremental search.
`keymap'
Sets Readline's idea of the current keymap for key binding
commands. Acceptable `keymap' names are `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 the `editing-mode'
variable also affects the default keymap.
`mark-directories'
If set to `on', completed directory names have a slash
appended. The default is `on'.
`mark-modified-lines'
This variable, when set to `on', causes Readline to display an
asterisk (`*') at the start of history lines which have been
modified. This variable is `off' by default.
`mark-symlinked-directories'
If set to `on', completed names which are symbolic links to
directories have a slash appended (subject to the value of
`mark-directories'). The default is `off'.
`match-hidden-files'
This variable, when set to `on', causes Readline to match
files whose names begin with a `.' (hidden files) when
performing filename completion, unless the leading `.' is
supplied by the user in the filename to be completed. This
variable is `on' by default.
`output-meta'
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'.
`page-completions'
If set to `on', Readline uses an internal `more'-like pager
to display a screenful of possible completions at a time.
This variable is `on' by default.
`print-completions-horizontally'
If set to `on', Readline will display completions with matches
sorted horizontally in alphabetical order, rather than down
the screen. The default is `off'.
`show-all-if-ambiguous'
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. The default value is `off'.
`show-all-if-unmodified'
This alters the default behavior of the completion functions
in a fashion similar to SHOW-ALL-IF-AMBIGUOUS. If set to
`on', words which have more than one possible completion
without any possible partial completion (the possible
completions don't share a common prefix) cause the matches to
be listed immediately instead of ringing the bell. The
default value is `off'.
`visible-stats'
If set to `on', a character denoting a file's type is
appended to the filename when listing possible completions.
The default is `off'.
Key Bindings
The syntax for controlling key bindings in the init file is
simple. First you need to find the name of the command that you
want to change. The following sections contain tables of the
command name, the default keybinding, if any, and a short
description of what the command does.
Once you know the name of the command, simply place on a line in
the init file the name of the key you wish to bind the command to,
a colon, and then the name of the command. There can be no space
between the key name and the colon - that will be interpreted as
part of the key name. The name of the key can be expressed in
different ways, depending on what you find most comfortable.
In addition to command names, readline allows keys to be bound to
a string that is inserted when the key is pressed (a MACRO).
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).
A number of symbolic character names are recognized while
processing this key binding syntax: DEL, ESC, ESCAPE, LFD,
NEWLINE, RET, RETURN, RUBOUT, SPACE, SPC, and TAB.
"KEYSEQ": FUNCTION-NAME or MACRO
KEYSEQ differs from KEYNAME above in that strings denoting an
entire key sequence can be specified, by placing the key
sequence in double quotes. Some GNU Emacs style key escapes
can be used, as in the following example, but the special
character names are not recognized.
"\C-u": universal-argument
"\C-x\C-r": re-read-init-file
"\e[11~": "Function Key 1"
In the above example, `C-u' is again bound to the function
`universal-argument' (just as it was in the first example),
`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 following GNU Emacs style escape sequences are available when
specifying key sequences:
`\C-'
control prefix
`\M-'
meta prefix
`\e'
an escape character
`\\'
backslash
`\"'
<">, a double quotation mark
`\''
<'>, a single quote or apostrophe
In addition to the GNU Emacs style escape sequences, a second set
of backslash escapes is available:
`\a'
alert (bell)
`\b'
backspace
`\d'
delete
`\f'
form feed
`\n'
newline
`\r'
carriage return
`\t'
horizontal tab
`\v'
vertical tab
`\NNN'
the eight-bit character whose value is the octal value NNN
(one to three digits)
`\xHH'
the eight-bit character whose value is the hexadecimal value
HH (one or two hex digits)
When entering the text of a macro, single or double quotes must be
used to indicate a macro definition. Unquoted text is assumed to
be a function name. In the macro body, the backslash escapes
described above are expanded. Backslash will quote any other
character in the macro text, including `"' and `''. For example,
the following binding will make `C-x \' insert a single `\' into
the line:
"\C-x\\": "\\"
Info Catalog
(readline.info.gz) Readline Init File
(readline.info.gz) Conditional Init Constructs
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