Readline Library
Version 2.1, September 1997
Brian Fox, Free Software Foundation
Chet Ramey, Case Western Reserve University
@dircategory Libraries @direntry * Readline: (readline). The GNU readline library API
This document describes the GNU Readline Library, a utility which aids in the consistency of user interface across discrete programs that need to provide a command line interface.
Published by the Free Software Foundation
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Cambridge, MA 02139 USA
Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies.
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Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that this permission notice may be stated in a translation approved by the Foundation.
Copyright (C) 1989, 1991 Free Software Foundation, Inc.
Index
- Command Line Editing
- Programming with GNU Readline
- Concept Index
- Function and Variable Index
Command Line Editing
This chapter describes the basic features of the GNU command line editing interface.Introduction to Line Editing
The following paragraphs describe the notation used to represent keystrokes.The text C-k is read as 'Control-K' and describes the character produced when the k key is pressed while the Control key is depressed.
The text M-k is read as 'Meta-K' and describes the character produced when the meta key (if you have one) is depressed, and the k key is pressed. If you do not have a meta key, the identical keystroke can be generated by typing ESC first, and then typing k. Either process is known as metafying the k key.
The text M-C-k is read as 'Meta-Control-k' and describes the character produced by metafying C-k.
In addition, several keys have their own names. Specifically, DEL, ESC, LFD, SPC, RET, and TAB all stand for themselves when seen in this text, or in an init file (@xref{Readline Init File}).
Readline Interaction
Often during an interactive session you type in a long line of text, only to notice that the first word on the line is misspelled. The Readline library gives you a set of commands for manipulating the text as you type it in, allowing you to just fix your typo, and not forcing you to retype the majority of the line. Using these editing commands, you move the cursor to the place that needs correction, and delete or insert the text of the corrections. Then, when you are satisfied with the line, you simply press RETURN. You do not have to be at the end of the line to press RETURN; the entire line is accepted regardless of the location of the cursor within the line.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 (see section 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. Here is how to change from the default Emacs-like key binding to usevi
line editing commands:set editing-mode vi
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.
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 he wants to see the list of possibilities. 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. 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 prepending 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'.
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'.
keymap
-
Sets Readline's idea of the current keymap for key binding commands.
Acceptable
keymap
names areemacs
,emacs-standard
,emacs-meta
,emacs-ctlx
,vi
,vi-command
, andvi-insert
.vi
is equivalent tovi-command
;emacs
is equivalent toemacs-standard
. The default value isemacs
. The value of theediting-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.
input-meta
-
If set to 'on', Readline will enable eight-bit input
(it will not strip the eighth bit from 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. 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'.
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'.
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 have to know 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 the name of the key you wish to bind the command to, a colon, and then the name of the command on a line in the init file. The name of the key can be expressed in different ways, depending on which is most comfortable for you.
- 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 functionuniversal-argument
, 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). - "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 bound to the functionuniversal-argument
(just as it was in the first example), 'C-x C-r' is bound to the functionre-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
\"
- "
\'
- '
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 character whose ASCII code is the octal value nnn (one to three digits)
\xnnn
- the character whose ASCII code is the hexadecimal value nnn (one to three 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\\": "\\"
Conditional Init Constructs
Readline implements a facility similar in spirit to the conditional compilation features of the C preprocessor which allows key bindings and variable settings to be performed as the result of tests. There are four parser directives used.$if
-
The
$if
construct allows bindings to be made based on the editing mode, the terminal being used, or the application using Readline. The text of the test extends to the end of the line; no characters are required to isolate it.
mode
-
The
mode=
form of the$if
directive is used to test whether Readline is inemacs
orvi
mode. This may be used in conjunction with the 'set keymap' command, for instance, to set bindings in theemacs-standard
andemacs-ctlx
keymaps only if Readline is starting out inemacs
mode. term
-
The
term=
form may be used to include terminal-specific key bindings, perhaps to bind the key sequences output by the terminal's function keys. The word on the right side of the '=' is tested against both the full name of the terminal and the portion of the terminal name before the first '-'. This allowssun
to match bothsun
andsun-cmd
, for instance. application
-
The application construct is used to include application-specific settings.
Each program using the Readline library sets the application name,
and you can test for it. 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
$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.
$include /etc/inputrc
Sample Init File
Here is an example of an inputrc file. This illustrates key binding, variable assignment, and conditional syntax.# This file controls the behaviour of line input editing for # programs that use the Gnu Readline library. Existing programs # include FTP, Bash, and Gdb. # # You can re-read the inputrc file with C-x C-r. # Lines beginning with '#' are comments. # # First, include any systemwide bindings and variable assignments from # /etc/Inputrc $include /etc/Inputrc # # Set various bindings for emacs mode. set editing-mode emacs $if mode=emacs Meta-Control-h: backward-kill-word Text after the function name is ignored # # Arrow keys in keypad mode # #"\M-OD": backward-char #"\M-OC": forward-char #"\M-OA": previous-history #"\M-OB": next-history # # Arrow keys in ANSI mode # "\M-[D": backward-char "\M-[C": forward-char "\M-[A": previous-history "\M-[B": next-history # # Arrow keys in 8 bit keypad mode # #"\M-\C-OD": backward-char #"\M-\C-OC": forward-char #"\M-\C-OA": previous-history #"\M-\C-OB": next-history # # Arrow keys in 8 bit ANSI mode # #"\M-\C-[D": backward-char #"\M-\C-[C": forward-char #"\M-\C-[A": previous-history #"\M-\C-[B": next-history C-q: quoted-insert $endif # An old-style binding. This happens to be the default. TAB: complete # Macros that are convenient for shell interaction $if Bash # edit the path "\C-xp": "PATH=${PATH}\e\C-e\C-a\ef\C-f" # prepare to type a quoted word -- insert open and close double quotes # and move to just after the open quote "\C-x\"": "\"\"\C-b" # insert a backslash (testing backslash escapes in sequences and macros) "\C-x\\": "\\" # Quote the current or previous word "\C-xq": "\eb\"\ef\"" # Add a binding to refresh the line, which is unbound "\C-xr": redraw-current-line # Edit variable on current line. "\M-\C-v": "\C-a\C-k$\C-y\M-\C-e\C-a\C-y=" $endif # use a visible bell if one is available set bell-style visible # don't strip characters to 7 bits when reading set input-meta on # allow iso-latin1 characters to be inserted rather than converted to # prefix-meta sequences set convert-meta off # display characters with the eighth bit set directly rather than # as meta-prefixed characters set output-meta on # if there are more than 150 possible completions for a word, ask the # user if he wants to see all of them set completion-query-items 150 # For FTP $if Ftp "\C-xg": "get \M-?" "\C-xt": "put \M-?" "\M-.": yank-last-arg $endif
Bindable Readline Commands
This section describes Readline commands that may be bound to key sequences.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 letters and digits.
backward-word (M-b)
- Move back to the start of this, or the previous, word. Words are composed of letters and digits.
clear-screen (C-l)
- Clear the screen and redraw the current line, leaving the current line at the top of the screen.
redraw-current-line ()
- Refresh the current line. By default, this is unbound.
Commands For Manipulating The History
accept-line (Newline, Return)
- Accept the line regardless of where the cursor is. If this line is non-empty, add it to the history list. If this line was a history line, then restore the history line to its original state.
previous-history (C-p)
- Move 'up' through the history list.
next-history (C-n)
- Move 'down' through the history 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 the history as necessary. This is an incremental search.
non-incremental-reverse-search-history (M-p)
- Search backward starting at the current line and moving 'up' through the history as necessary using a non-incremental search for a string supplied by the user.
non-incremental-forward-search-history (M-n)
- Search forward starting at the current line and moving 'down' through the the history as necessary using a non-incremental search for a string supplied by the user.
history-search-forward ()
- Search forward through the history for the string of characters between the start of the current line and the current cursor position (the point). This is a non-incremental search. By default, this command is unbound.
history-search-backward ()
- Search backward through the history for the string of characters between the start of the current line and the point. This is a non-incremental search. By default, this command is unbound.
yank-nth-arg (M-C-y)
- Insert the first argument to the previous command (usually the second word on the previous line). With an argument n, insert the nth word from the previous command (the words in the previous command begin with word 0). A negative argument inserts the nth word from the end of the previous command.
yank-last-arg (M-., M-_)
-
Insert last argument to the previous command (the last word of
the previous history entry). With an argument,
behave exactly like
yank-nth-arg
. Successive calls toyank-last-arg
move back through the history list, inserting the last argument of each line in turn.
Commands For Changing Text
delete-char (C-d)
-
Delete the character under the cursor. If the cursor is at the beginning of
the line, there are no characters in the line, and the last character typed
was not bound to
delete-char
, then returnEOF
. backward-delete-char (Rubout)
- Delete the character behind the cursor. A numeric argument means to kill the characters instead of deleting them.
quoted-insert (C-q, C-v)
- Add the next character typed to the line verbatim. This is how to insert key sequences like C-q, for example.
tab-insert (M-TAB)
- Insert a tab character.
self-insert (a, b, A, 1, !, ...)
- Insert yourself.
transpose-chars (C-t)
- Drag the character before the cursor forward over the character at the cursor, moving the cursor forward as well. If the insertion point is at the end of the line, then this transposes the last two characters of the line. Negative arguments don't work.
transpose-words (M-t)
- Drag the word behind the cursor past the word in front of the cursor moving the cursor over that word as well.
upcase-word (M-u)
- Uppercase the current (or following) word. With a negative argument, uppercase the previous word, but do not move the cursor.
downcase-word (M-l)
- Lowercase the current (or following) word. With a negative argument, lowercase the previous word, but do not move the cursor.
capitalize-word (M-c)
- Capitalize the current (or following) word. With a negative argument, capitalize the previous word, but do not move the cursor.
Killing And Yanking
kill-line (C-k)
- Kill the text from the current cursor position 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 the cursor to the beginning of the current line. The killed text is saved on the kill-ring.
kill-whole-line ()
- Kill all characters on the current line, no matter where the cursor is. By default, this is unbound.
kill-word (M-d)
-
Kill from the cursor to the end of the current word, or if between words,
to the end of the next word. Word boundaries are the same as
forward-word
. backward-kill-word (M-DEL)
-
Kill the word behind the cursor. Word boundaries are the same as
backward-word
. unix-word-rubout (C-w)
- Kill the word behind the cursor, using white space as a word boundary. The killed text is saved on the kill-ring.
delete-horizontal-space ()
- Delete all spaces and tabs around point. By default, this is unbound.
kill-region ()
- Kill the text between the point and the mark (saved cursor position). This text is referred to as the region. By default, this command is unbound.
copy-region-as-kill ()
- Copy the text in the region to the kill buffer, so it can be yanked right away. By default, this command is unbound.
copy-backward-word ()
-
Copy the word before point to the kill buffer.
The word boundaries are the same as
backward-word
. By default, this command is unbound. copy-forward-word ()
-
Copy the word following point to the kill buffer.
The word boundaries are the same as
forward-word
. By default, this command is unbound. yank (C-y)
- Yank the top of the kill ring into the buffer at the current cursor position.
yank-pop (M-y)
- Rotate the kill-ring, and yank the new top. You can only do this if the prior command is yank or yank-pop.
Specifying Numeric Arguments
digit-argument (M-0, M-1, ... M--)
- Add this digit to the argument already accumulating, or start a new argument. M-- starts a negative argument.
universal-argument ()
-
This is another way to specify an argument.
If this command is followed by one or more digits, optionally with
a leading minus sign, those digits define the argument.
If the command is followed by digits, executing
universal-argument
again ends the numeric argument, but is otherwise ignored. As a special case, if this command is immediately followed by a character that is neither a digit or minus sign, the argument count for the next command is multiplied by four. The argument count is initially one, so executing this function the first time makes the argument count four, a second time makes the argument count sixteen, and so on. By default, this is not bound to a key.
Letting Readline Type For You
complete (TAB)
- Attempt to do completion on the text before the cursor. This is application-specific. Generally, if you are typing a filename argument, you can do filename completion; if you are typing a command, you can do command completion; if you are typing in a symbol to GDB, you can do symbol name completion; if you are typing in a variable to Bash, you can do variable name completion, and so on.
possible-completions (M-?)
- List the possible completions of the text before the cursor.
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 ofmenu-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 and the original text is restored. An argument of n moves n positions forward in the list of matches; a negative argument may be used to move backward through the list. This command is intended to be bound toTAB
, but is unbound by default.
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 save the definition.
call-last-kbd-macro (C-x e)
- Re-execute the last keyboard macro defined, by making the characters in the macro appear as if typed at the keyboard.
Some Miscellaneous Commands
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-uppercase-version (M-a, M-b, M-x, ...)
- If the metafied character x is lowercase, run the command that is bound to the corresponding uppercase character.
prefix-meta (ESC)
- Make the next character typed be metafied. This is for keyboards without a meta key. Typing 'ESC f' is equivalent to typing 'M-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 get back to the beginning. tilde-expand (M-~)
- Perform tilde expansion on the current word.
set-mark (C-@)
- Set the mark to the current point. If a numeric argument is supplied, the mark is set to that position.
exchange-point-and-mark (C-x C-x)
- Swap the point with the mark. The current cursor position is set to the saved position, and the old cursor position is saved as the mark.
character-search (C-])
- A character is read and point is moved to the next occurrence of that character. A negative count searches for previous occurrences.
character-search-backward (M-C-])
- A character is read and point is moved to the previous occurrence of that character. A negative count searches for subsequent occurrences.
insert-comment (M-#)
-
The value of the
comment-begin
variable is inserted at the beginning of the current line, and the line is accepted as if a newline had been typed. dump-functions ()
- Print all of the functions and their key bindings to the Readline output stream. If a numeric argument is supplied, the output is formatted in such a way that it can be made part of an inputrc file. This command is unbound by default.
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. This command is unbound by default.
dump-macros ()
- Print all of the Readline key sequences bound to macros and the strings they ouput. If a numeric argument is supplied, the output is formatted in such a way that it can be made part of an inputrc file. This command is unbound by default.
Readline vi Mode
While the Readline library does not have a full set ofvi
editing functions, it does contain enough to allow simple editing of the line.
The Readline vi
mode behaves as specified in the POSIX 1003.2 standard.
In order to switch interactively between
emacs
and vi
editing modes, use the command M-C-j (toggle-editing-mode).
The Readline default is emacs
mode.
When you enter a line in
vi
mode, you are already placed in
'insertion' mode, as if you had typed an 'i'. Pressing ESC
switches you into 'command' mode, where you can edit the text of the line
with the standard vi
movement keys, move to previous history lines
with 'k' and subsequent lines with 'j', and so forth.
Programming with GNU Readline
This chapter describes the interface between the GNU Readline Library and other programs. If you are a programmer, and you wish to include the features found in GNU Readline such as completion, line editing, and interactive history manipulation in your own programs, this section is for you.Basic Behavior
Many programs provide a command line interface, such asmail
,
ftp
, and sh
. For such programs, the default behaviour of
Readline is sufficient. This section describes how to use Readline in
the simplest way possible, perhaps to replace calls in your code to
gets()
or fgets ()
.
The function
readline ()
prints a prompt and then reads and returns
a single line of text from the user. The line readline
returns is allocated with malloc ()
; you should free ()
the line when you are done with it. The declaration for readline
in ANSI C is
char *readline (char *prompt);
So, one might say
char *line = readline ("Enter a line: ");
in order to read a line of text from the user.
The line returned has the final newline removed, so only the
text remains.
If
readline
encounters an EOF
while reading the line, and the
line is empty at that point, then (char *)NULL
is returned.
Otherwise, the line is ended just as if a newline had been typed.
If you want the user to be able to get at the line later, (with C-p for example), you must call
add_history ()
to save the
line away in a history list of such lines.
add_history (line)
;
For full details on the GNU History Library, see the associated manual.
It is preferable to avoid saving empty lines on the history list, since users rarely have a burning need to reuse a blank line. Here is a function which usefully replaces the standard
gets ()
library
function, and has the advantage of no static buffer to overflow:
/* A static variable for holding the line. */ static char *line_read = (char *)NULL; /* Read a string, and return a pointer to it. Returns NULL on EOF. */ char * rl_gets () { /* If the buffer has already been allocated, return the memory to the free pool. */ if (line_read) { free (line_read); line_read = (char *)NULL; } /* Get a line from the user. */ line_read = readline (""); /* If the line has any text in it, save it on the history. */ if (line_read && *line_read) add_history (line_read); return (line_read); }This function gives the user the default behaviour of TAB completion: completion on file names. If you do not want Readline to complete on filenames, you can change the binding of the TAB key with
rl_bind_key ()
.
int rl_bind_key (int key, int (*function)());
rl_bind_key ()
takes two arguments: key is the character
that you want to bind, and function is the address of the function
to call when key is pressed.
Binding TAB to rl_insert ()
makes TAB insert itself.
rl_bind_key ()
returns non-zero if key is not a valid
ASCII character code (between 0 and 255).
Thus, to disable the default TAB behavior, the following suffices:
rl_bind_key ('\t', rl_insert);
This code should be executed once at the start of your program;
you might write a function called initialize_readline ()
which
performs this and other desired initializations, such as installing
custom completers (see section Custom Completers).
Custom Functions
Readline provides many functions for manipulating the text of the line, but it isn't possible to anticipate the needs of all programs. This section describes the various functions and variables defined within the Readline library which allow a user program to add customized functionality to Readline.The Function Type
For readabilty, we declare a new type of object, called Function. AFunction
is a C function which returns an int
.
The type declaration for Function
is:
typedef int Function ();
The reason for declaring this new type is to make it easier to write
code describing pointers to C functions. Let us say we had a variable
called func which was a pointer to a function. Instead of the
classic C declaration
int (*)()func;
we may write
Function *func;
Similarly, there are
typedef void VFunction (); typedef char *CPFunction (); and typedef char **CPPFunction ();for functions returning no value,
pointer to char
, and
pointer to pointer to char
, respectively.
Writing a New Function
In order to write new functions for Readline, you need to know the calling conventions for keyboard-invoked functions, and the names of the variables that describe the current state of the line read so far.The calling sequence for a command
foo
looks like
foo (int count, int key)
where count is the numeric argument (or 1 if defaulted) and
key is the key that invoked this function.
It is completely up to the function as to what should be done with the numeric argument. Some functions use it as a repeat count, some as a flag, and others to choose alternate behavior (refreshing the current line as opposed to refreshing the screen, for example). Some choose to ignore it. In general, if a function uses the numeric argument as a repeat count, it should be able to do something useful with both negative and positive arguments. At the very least, it should be aware that it can be passed a negative argument.
Readline Variables
These variables are available to function writers.- Variable: char * rl_line_buffer
- This is the line gathered so far. You are welcome to modify the contents of the line, but see section Allowing Undoing.
- Variable: int rl_point
-
The offset of the current cursor position in
rl_line_buffer
(the point). - Variable: int rl_end
-
The number of characters present in
rl_line_buffer
. Whenrl_point
is at the end of the line,rl_point
andrl_end
are equal. - Variable: int rl_mark
- The mark (saved position) in the current line. If set, the mark and point define a region.
- Variable: int rl_done
- Setting this to a non-zero value causes Readline to return the current line immediately.
- Variable: int rl_pending_input
- Setting this to a value makes it the next keystroke read. This is a way to stuff a single character into the input stream.
- Variable: char * rl_prompt
-
The prompt Readline uses. This is set from the argument to
readline ()
, and should not be assigned to directly. - Variable: char * rl_library_version
- The version number of this revision of the library.
- Variable: char * rl_terminal_name
- The terminal type, used for initialization.
- Variable: char * rl_readline_name
- This variable is set to a unique name by each application using Readline. The value allows conditional parsing of the inputrc file (see section Conditional Init Constructs).
- Variable: FILE * rl_instream
- The stdio stream from which Readline reads input.
- Variable: FILE * rl_outstream
- The stdio stream to which Readline performs output.
- Variable: Function * rl_startup_hook
-
If non-zero, this is the address of a function to call just
before
readline
prints the first prompt. - Variable: Function * rl_event_hook
- If non-zero, this is the address of a function to call periodically when readline is waiting for terminal input.
- Variable: Function * rl_getc_function
-
If non-zero,
readline
will call indirectly through this pointer to get a character from the input stream. By default, it is set torl_getc
, the defaultreadline
character input function (see section Utility Functions). - Variable: VFunction * rl_redisplay_function
-
If non-zero,
readline
will call indirectly through this pointer to update the display with the current contents of the editing buffer. By default, it is set torl_redisplay
, the defaultreadline
redisplay function (see section Redisplay). - Variable: Keymap rl_executing_keymap
- This variable is set to the keymap (see section Selecting a Keymap) in which the currently executing readline function was found.
- Variable: Keymap rl_binding_keymap
- This variable is set to the keymap (see section Selecting a Keymap) in which the last key binding occurred.
Readline Convenience Functions
Naming a Function
The user can dynamically change the bindings of keys while using Readline. This is done by representing the function with a descriptive name. The user is able to type the descriptive name when referring to the function. Thus, in an init file, one might findMeta-Rubout: backward-kill-wordThis binds the keystroke Meta-Rubout to the function descriptively named
backward-kill-word
.
You, as the programmer, should bind the functions you write to descriptive names
as well. Readline provides a function for doing that:
- Function: int rl_add_defun (char *name, Function *function, int key)
-
Add name to the list of named functions. Make function be
the function that gets called. If key is not -1, then bind it to
function using
rl_bind_key ()
.
Selecting a Keymap
Key bindings take place on a keymap. The keymap is the association between the keys that the user types and the functions that get run. You can make your own keymaps, copy existing keymaps, and tell Readline which keymap to use.- Function: Keymap rl_make_bare_keymap ()
-
Returns a new, empty keymap. The space for the keymap is allocated with
malloc ()
; you shouldfree ()
it when you are done. - Function: Keymap rl_copy_keymap (Keymap map)
- Return a new keymap which is a copy of map.
- Function: Keymap rl_make_keymap ()
- Return a new keymap with the printing characters bound to rl_insert, the lowercase Meta characters bound to run their equivalents, and the Meta digits bound to produce numeric arguments.
- Function: void rl_discard_keymap (Keymap keymap)
- Free the storage associated with keymap.
- Function: Keymap rl_get_keymap ()
- Returns the currently active keymap.
- Function: void rl_set_keymap (Keymap keymap)
- Makes keymap the currently active keymap.
- Function: Keymap rl_get_keymap_by_name (char *name)
-
Return the keymap matching name. name is one which
would be supplied in a
set keymap
inputrc line (@xref{Readline Init File}). - Function: char * rl_get_keymap_name (Keymap keymap)
-
Return the name matching keymap. name is one which
would be supplied in a
set keymap
inputrc line (@xref{Readline Init File}).
Binding Keys
You associate keys with functions through the keymap. Readline has several internal keymaps:emacs_standard_keymap
,
emacs_meta_keymap
, emacs_ctlx_keymap
,
vi_movement_keymap
, and vi_insertion_keymap
.
emacs_standard_keymap
is the default, and the examples in
this manual assume that.
These functions manage key bindings.
- Function: int rl_bind_key (int key, Function *function)
- Binds key to function in the currently active keymap. Returns non-zero in the case of an invalid key.
- Function: int rl_bind_key_in_map (int key, Function *function, Keymap map)
- Bind key to function in map. Returns non-zero in the case of an invalid key.
- Function: int rl_unbind_key (int key)
- Bind key to the null function in the currently active keymap. Returns non-zero in case of error.
- Function: int rl_unbind_key_in_map (int key, Keymap map)
- Bind key to the null function in map. Returns non-zero in case of error.
- Function: int rl_unbind_function_in_map (Function *function, Keymap map)
- Unbind all keys that execute function in map.
- Function: int rl_unbind_command_in_map (char *command, Keymap map)
- Unbind all keys that are bound to command in map.
- Function: int rl_generic_bind (int type, char *keyseq, char *data, Keymap map)
-
Bind the key sequence represented by the string keyseq to the arbitrary
pointer data. type says what kind of data is pointed to by
data; this can be a function (
ISFUNC
), a macro (ISMACR
), or a keymap (ISKMAP
). This makes new keymaps as necessary. The initial keymap in which to do bindings is map. - Function: int rl_parse_and_bind (char *line)
-
Parse line as if it had been read from the
inputrc
file and perform any key bindings and variable assignments found (@xref{Readline Init File}). - Function: int rl_read_init_file (char *filename)
- Read keybindings and variable assignments from filename (@xref{Readline Init File}).
Associating Function Names and Bindings
These functions allow you to find out what keys invoke named functions and the functions invoked by a particular key sequence.- Function: Function * rl_named_function (char *name)
- Return the function with name name.
- Function: Function * rl_function_of_keyseq (char *keyseq, Keymap map, int *type)
-
Return the function invoked by keyseq in keymap map.
If map is NULL, the current keymap is used. If type is
not NULL, the type of the object is returned in it (one of
ISFUNC
,ISKMAP
, orISMACR
). - Function: char ** rl_invoking_keyseqs (Function *function)
- Return an array of strings representing the key sequences used to invoke function in the current keymap.
- Function: char ** rl_invoking_keyseqs_in_map (Function *function, Keymap map)
- Return an array of strings representing the key sequences used to invoke function in the keymap map.
- Function: void rl_function_dumper (int readable)
-
Print the readline function names and the key sequences currently bound to them
to
rl_outstream
. If readable is non-zero, the list is formatted in such a way that it can be made part of aninputrc
file and re-read. - Function: void rl_list_funmap_names ()
-
Print the names of all bindable Readline functions to
rl_outstream
.
Allowing Undoing
Supporting the undo command is a painless thing, and makes your functions much more useful. It is certainly easy to try something if you know you can undo it. I could use an undo function for the stock market.If your function simply inserts text once, or deletes text once, and uses
rl_insert_text ()
or rl_delete_text ()
to do it, then
undoing is already done for you automatically.
If you do multiple insertions or multiple deletions, or any combination of these operations, you should group them together into one operation. This is done with
rl_begin_undo_group ()
and
rl_end_undo_group ()
.
The types of events that can be undone are:
enum undo_code { UNDO_DELETE, UNDO_INSERT, UNDO_BEGIN, UNDO_END };Notice that
UNDO_DELETE
means to insert some text, and
UNDO_INSERT
means to delete some text. That is, the undo code
tells undo what to undo, not how to undo it. UNDO_BEGIN
and
UNDO_END
are tags added by rl_begin_undo_group ()
and
rl_end_undo_group ()
.
- Function: int rl_begin_undo_group ()
-
Begins saving undo information in a group construct. The undo information
usually comes from calls to
rl_insert_text ()
andrl_delete_text ()
, but could be the result of calls torl_add_undo ()
. - Function: int rl_end_undo_group ()
-
Closes the current undo group started with
rl_begin_undo_group ()
. There should be one call torl_end_undo_group ()
for each call torl_begin_undo_group ()
. - Function: void rl_add_undo (enum undo_code what, int start, int end, char *text)
- Remember how to undo an event (according to what). The affected text runs from start to end, and encompasses text.
- Function: void free_undo_list ()
- Free the existing undo list.
- Function: int rl_do_undo ()
-
Undo the first thing on the undo list. Returns
0
if there was nothing to undo, non-zero if something was undone.
rl_modifying ()
once, just before you modify the text. You must supply the indices of
the text range that you are going to modify.
- Function: int rl_modifying (int start, int end)
- Tell Readline to save the text between start and end as a single undo unit. It is assumed that you will subsequently modify that text.
Redisplay
- Function: void rl_redisplay ()
-
Change what's displayed on the screen to reflect the current contents
of
rl_line_buffer
. - Function: int rl_forced_update_display ()
- Force the line to be updated and redisplayed, whether or not Readline thinks the screen display is correct.
- Function: int rl_on_new_line ()
- Tell the update routines that we have moved onto a new (empty) line, usually after ouputting a newline.
- Function: int rl_reset_line_state ()
- Reset the display state to a clean state and redisplay the current line starting on a new line.
- Function: int rl_message (va_alist)
-
The arguments are a string as would be supplied to
printf
. The resulting string is displayed in the echo area. The echo area is also used to display numeric arguments and search strings. - Function: int rl_clear_message ()
- Clear the message in the echo area.
Modifying Text
- Function: int rl_insert_text (char *text)
- Insert text into the line at the current cursor position.
- Function: int rl_delete_text (int start, int end)
- Delete the text between start and end in the current line.
- Function: char * rl_copy_text (int start, int end)
- Return a copy of the text between start and end in the current line.
- Function: int rl_kill_text (int start, int end)
- Copy the text between start and end in the current line to the kill ring, appending or prepending to the last kill if the last command was a kill command. The text is deleted. If start is less than end, the text is appended, otherwise prepended. If the last command was not a kill, a new kill ring slot is used.
Utility Functions
- Function: int rl_read_key ()
-
Return the next character available. This handles input inserted into
the input stream via pending input
(see section Readline Variables)
and
rl_stuff_char ()
, macros, and characters read from the keyboard. - Function: int rl_getc (FILE *)
- Return the next character available from the keyboard.
- Function: int rl_stuff_char (int c)
-
Insert c into the Readline input stream. It will be "read"
before Readline attempts to read characters from the terminal with
rl_read_key ()
. - Function: rl_extend_line_buffer (int len)
-
Ensure that
rl_line_buffer
has enough space to hold len characters, possibly reallocating it if necessary. - Function: int rl_initialize ()
- Initialize or re-initialize Readline's internal state.
- Function: int rl_reset_terminal (char *terminal_name)
-
Reinitialize Readline's idea of the terminal settings using
terminal_name as the terminal type (e.g.,
vt100
). - Function: int alphabetic (int c)
- Return 1 if c is an alphabetic character.
- Function: int numeric (int c)
- Return 1 if c is a numeric character.
- Function: int ding ()
-
Ring the terminal bell, obeying the setting of
bell-style
.
chartypes.h
.
- Function: int uppercase_p (int c)
- Return 1 if c is an uppercase alphabetic character.
- Function: int lowercase_p (int c)
- Return 1 if c is a lowercase alphabetic character.
- Function: int digit_p (int c)
- Return 1 if c is a numeric character.
- Function: int to_upper (int c)
- If c is a lowercase alphabetic character, return the corresponding uppercase character.
- Function: int to_lower (int c)
- If c is an uppercase alphabetic character, return the corresponding lowercase character.
- Function: int digit_value (int c)
- If c is a number, return the value it represents.
Alternate Interface
An alternate interface is available to plainreadline()
.
Some applications need to interleave keyboard I/O with file, device, or
window system I/O, typically by using a main loop to select()
on various file descriptors. To accomodate this need,
readline can also be invoked as a 'callback' function from an event loop.
There are functions available to make this easy.
- Function: void rl_callback_handler_install (char *prompt, Vfunction *lhandler)
- Set up the terminal for readline I/O and display the initial expanded value of prompt. Save the value of lhandler to use as a callback when a complete line of input has been entered.
- Function: void rl_callback_read_char ()
-
Whenever an application determines that keyboard input is available,
it should call
rl_callback_read_char()
, which will read the next character from the current input source. If that character completes the line,rl_callback_read_char
will invoke the lhandler function saved byrl_callback_handler_install
to process the line.EOF
is indicated by calling lhandler with aNULL
line. - Function: void rl_callback_handler_remove ()
- Restore the terminal to its initial state and remove the line handler. This may be called from within a callback as well as independently.
An Example
Here is a function which changes lowercase characters to their uppercase equivalents, and uppercase characters to lowercase. If this function was bound to 'M-c', then typing 'M-c' would change the case of the character under point. Typing 'M-1 0 M-c' would change the case of the following 10 characters, leaving the cursor on the last character changed./* Invert the case of the COUNT following characters. */ int invert_case_line (count, key) int count, key; { register int start, end, i; start = rl_point; if (rl_point >= rl_end) return (0); if (count < 0) { direction = -1; count = -count; } else direction = 1; /* Find the end of the range to modify. */ end = start + (count * direction); /* Force it to be within range. */ if (end > rl_end) end = rl_end; else if (end < 0) end = 0; if (start == end) return (0); if (start > end) { int temp = start; start = end; end = temp; } /* Tell readline that we are modifying the line, so it will save the undo information. */ rl_modifying (start, end); for (i = start; i != end; i++) { if (uppercase_p (rl_line_buffer[i])) rl_line_buffer[i] = to_lower (rl_line_buffer[i]); else if (lowercase_p (rl_line_buffer[i])) rl_line_buffer[i] = to_upper (rl_line_buffer[i]); } /* Move point to on top of the last character changed. */ rl_point = (direction == 1) ? end - 1 : start; return (0); }
Custom Completers
Typically, a program that reads commands from the user has a way of disambiguating commands and data. If your program is one of these, then it can provide completion for commands, data, or both. The following sections describe how your program and Readline cooperate to provide this service.How Completing Works
In order to complete some text, the full list of possible completions must be available. That is, it is not possible to accurately expand a partial word without knowing all of the possible words which make sense in that context. The Readline library provides the user interface to completion, and two of the most common completion functions: filename and username. For completing other types of text, you must write your own completion function. This section describes exactly what such functions must do, and provides an example.There are three major functions used to perform completion:
- The user-interface function
rl_complete ()
. This function is called with the same arguments as other Readline functions intended for interactive use: count and invoking_key. It isolates the word to be completed and callscompletion_matches ()
to generate a list of possible completions. It then either lists the possible completions, inserts the possible completions, or actually performs the completion, depending on which behavior is desired. - The internal function
completion_matches ()
uses your generator function to generate the list of possible matches, and then returns the array of these matches. You should place the address of your generator function inrl_completion_entry_function
. - The generator function is called repeatedly from
completion_matches ()
, returning a string each time. The arguments to the generator function are text and state. text is the partial word to be completed. state is zero the first time the function is called, allowing the generator to perform any necessary initialization, and a positive non-zero integer for each subsequent call. When the generator function returns(char *)NULL
this signalscompletion_matches ()
that there are no more possibilities left. Usually the generator function computes the list of possible completions when state is zero, and returns them one at a time on subsequent calls. Each string the generator function returns as a match must be allocated withmalloc()
; Readline frees the strings when it has finished with them.
- Function: int rl_complete (int ignore, int invoking_key)
-
Complete the word at or before point. You have supplied the function
that does the initial simple matching selection algorithm
(see
completion_matches ()
). The default is to do filename completion. - Variable: Function * rl_completion_entry_function
-
This is a pointer to the generator function for
completion_matches ()
. If the value ofrl_completion_entry_function
is(Function *)NULL
then the default filename generator function,filename_completion_function ()
, is used.
Completion Functions
Here is the complete list of callable completion functions present in Readline.- Function: int rl_complete_internal (int what_to_do)
- Complete the word at or before point. what_to_do says what to do with the completion. A value of '?' means list the possible completions. 'TAB' means do standard completion. '*' means insert all of the possible completions. '!' means to display all of the possible completions, if there is more than one, as well as performing partial completion.
- Function: int rl_complete (int ignore, int invoking_key)
-
Complete the word at or before point. You have supplied the function
that does the initial simple matching selection algorithm
(see
completion_matches ()
andrl_completion_entry_function
). The default is to do filename completion. This callsrl_complete_internal ()
with an argument depending on invoking_key. - Function: int rl_possible_completions (int count, int invoking_key))
-
List the possible completions. See description of
rl_complete ()
. This callsrl_complete_internal ()
with an argument of '?'. - Function: int rl_insert_completions (int count, int invoking_key))
-
Insert the list of possible completions into the line, deleting the
partially-completed word. See description of
rl_complete ()
. This callsrl_complete_internal ()
with an argument of '*'. - Function: char ** completion_matches (char *text, CPFunction *entry_func)
-
Returns an array of
(char *)
which is a list of completions for text. If there are no completions, returns(char **)NULL
. The first entry in the returned array is the substitution for text. The remaining entries are the possible completions. The array is terminated with aNULL
pointer.
entry_func is a function of two args, and returns a(char *)
. The first argument is text. The second is a state argument; it is zero on the first call, and non-zero on subsequent calls. entry_func returns aNULL
pointer to the caller when there are no more matches. - Function: char * filename_completion_function (char *text, int state)
- A generator function for filename completion in the general case. Note that completion in Bash is a little different because of all the pathnames that must be followed when looking up completions for a command. The Bash source is a useful reference for writing custom completion functions.
- Function: char * username_completion_function (char *text, int state)
- A completion generator for usernames. text contains a partial username preceded by a random character (usually '~'). As with all completion generators, state is zero on the first call and non-zero for subsequent calls.
Completion Variables
- Variable: Function * rl_completion_entry_function
-
A pointer to the generator function for
completion_matches ()
.NULL
means to usefilename_entry_function ()
, the default filename completer. - Variable: CPPFunction * rl_attempted_completion_function
-
A pointer to an alternative function to create matches.
The function is called with text, start, and end.
start and end are indices in
rl_line_buffer
saying what the boundaries of text are. If this function exists and returnsNULL
, or if this variable is set toNULL
, thenrl_complete ()
will call the value ofrl_completion_entry_function
to generate matches, otherwise the array of strings returned will be used. - Variable: CPFunction * rl_filename_quoting_function
-
A pointer to a function that will quote a filename in an application-specific fashion.
This is called if filename completion is being attempted and one of the characters
in
rl_filename_quote_characters
appears in a completed filename. The function is called with text, match_type, and quote_pointer. The text is the filename to be quoted. The match_type is eitherSINGLE_MATCH
, if there is only one completion match, orMULT_MATCH
. Some functions use this to decide whether or not to insert a closing quote character. The quote_pointer is a pointer to any opening quote character the user typed. Some functions choose to reset this character. - Variable: CPFunction * rl_filename_dequoting_function
- A pointer to a function that will remove application-specific quoting characters from a filename before completion is attempted, so those characters do not interfere with matching the text against names in the filesystem. It is called with text, the text of the word to be dequoted, and quote_char, which is the quoting character that delimits the filename (usually ''' or '"'). If quote_char is zero, the filename was not in an embedded string.
- Variable: Function * rl_char_is_quoted_p
-
A pointer to a function to call that determines whether or not a specific
character in the line buffer is quoted, according to whatever quoting
mechanism the program calling readline uses. The function is called with
two arguments: text, the text of the line, and index,
the index of the character in the line. It is used to decide whether
a character found in
rl_completer_word_break_characters
should be used to break words for the completer. - Variable: int rl_completion_query_items
- Up to this many items will be displayed in response to a possible-completions call. After that, we ask the user if she is sure she wants to see them all. The default value is 100.
- Variable: char * rl_basic_word_break_characters
-
The basic list of characters that signal a break between words for the
completer routine. The default value of this variable is the characters
which break words for completion in Bash, i.e.,
" \t\n\"\\''@$><=;|&{("
. - Variable: char * rl_basic_quote_characters
- List of quote characters which can cause a word break.
- Variable: char * rl_completer_word_break_characters
-
The list of characters that signal a break between words for
rl_complete_internal ()
. The default list is the value ofrl_basic_word_break_characters
. - Variable: char * rl_completer_quote_characters
-
List of characters which can be used to quote a substring of the line.
Completion occurs on the entire substring, and within the substring
rl_completer_word_break_characters
are treated as any other character, unless they also appear within this list. - Variable: char * rl_filename_quote_characters
- A list of characters that cause a filename to be quoted by the completer when they appear in a completed filename. The default is the null string.
- Variable: char * rl_special_prefixes
- The list of characters that are word break characters, but should be left in text when it is passed to the completion function. Programs can use this to help determine what kind of completing to do. For instance, Bash sets this variable to "$@" so that it can complete shell variables and hostnames.
- Variable: int rl_completion_append_character
- When a single completion alternative matches at the end of the command line, this character is appended to the inserted completion text. The default is a space character (' '). Setting this to the null character ('\0') prevents anything being appended automatically. This can be changed in custom completion functions to provide the "most sensible word separator character" according to an application-specific command line syntax specification.
- Variable: int rl_ignore_completion_duplicates
- If non-zero, then disallow duplicates in the matches. Default is 1.
- Variable: int rl_filename_completion_desired
- Non-zero means that the results of the matches are to be treated as filenames. This is always zero on entry, and can only be changed within a completion entry generator function. If it is set to a non-zero value, directory names have a slash appended and Readline attempts to quote completed filenames if they contain any embedded word break characters.
- Variable: int rl_filename_quoting_desired
-
Non-zero means that the results of the matches are to be quoted using
double quotes (or an application-specific quoting mechanism) if the
completed filename contains any characters in
rl_filename_quote_chars
. This is always non-zero on entry, and can only be changed within a completion entry generator function. The quoting is effected via a call to the function pointed to byrl_filename_quoting_function
. - Variable: int rl_inhibit_completion
-
If this variable is non-zero, completion is inhibit<ed.
The completion character will be inserted as any other bound to
self-insert
. - Variable: Function * rl_ignore_some_completions_function
-
This function, if defined, is called by the completer when real filename
completion is done, after all the matching names have been generated.
It is passed a
NULL
terminated array of matches. The first element (matches[0]
) is the maximal substring common to all matches. This function can re-arrange the list of matches as required, but each element deleted from the array must be freed. - Variable: Function * rl_directory_completion_hook
- This function, if defined, is allowed to modify the directory portion of filenames Readline completes. It is called with the address of a string (the current directory name) as an argument. It could be used to expand symbolic links or shell variables in pathnames.
A Short Completion Example
Here is a small application demonstrating the use of the GNU Readline library. It is calledfileman
, and the source code resides in
'examples/fileman.c'. This sample application provides
completion of command names, line editing features, and access to the
history list.
/* fileman.c -- A tiny application which demonstrates how to use the GNU Readline library. This application interactively allows users to manipulate files and their modes. */ #include <stdio.h> #include <sys/types.h> #include <sys/file.h> #include <sys/stat.h> #include <sys/errno.h> #include <readline/readline.h> #include <readline/history.h> extern char *getwd (); extern char *xmalloc (); /* The names of functions that actually do the manipulation. */ int com_list (), com_view (), com_rename (), com_stat (), com_pwd (); int com_delete (), com_help (), com_cd (), com_quit (); /* A structure which contains information on the commands this program can understand. */ typedef struct { char *name; /* User printable name of the function. */ Function *func; /* Function to call to do the job. */ char *doc; /* Documentation for this function. */ } COMMAND; COMMAND commands[] = { { "cd", com_cd, "Change to directory DIR" }, { "delete", com_delete, "Delete FILE" }, { "help", com_help, "Display this text" }, { "?", com_help, "Synonym for 'help'" }, { "list", com_list, "List files in DIR" }, { "ls", com_list, "Synonym for 'list'" }, { "pwd", com_pwd, "Print the current working directory" }, { "quit", com_quit, "Quit using Fileman" }, { "rename", com_rename, "Rename FILE to NEWNAME" }, { "stat", com_stat, "Print out statistics on FILE" }, { "view", com_view, "View the contents of FILE" }, { (char *)NULL, (Function *)NULL, (char *)NULL } }; /* Forward declarations. */ char *stripwhite (); COMMAND *find_command (); /* The name of this program, as taken from argv[0]. */ char *progname; /* When non-zero, this global means the user is done using this program. */ int done; char * dupstr (s) int s; { char *r; r = xmalloc (strlen (s) + 1); strcpy (r, s); return (r); } main (argc, argv) int argc; char **argv; { char *line, *s; progname = argv[0]; initialize_readline (); /* Bind our completer. */ /* Loop reading and executing lines until the user quits. */ for ( ; done == 0; ) { line = readline ("FileMan: "); if (!line) break; /* Remove leading and trailing whitespace from the line. Then, if there is anything left, add it to the history list and execute it. */ s = stripwhite (line); if (*s) { add_history (s); execute_line (s); } free (line); } exit (0); } /* Execute a command line. */ int execute_line (line) char *line; { register int i; COMMAND *command; char *word; /* Isolate the command word. */ i = 0; while (line[i] && whitespace (line[i])) i++; word = line + i; while (line[i] && !whitespace (line[i])) i++; if (line[i]) line[i++] = '\0'; command = find_command (word); if (!command) { fprintf (stderr, "%s: No such command for FileMan.\n", word); return (-1); } /* Get argument to command, if any. */ while (whitespace (line[i])) i++; word = line + i; /* Call the function. */ return ((*(command->func)) (word)); } /* Look up NAME as the name of a command, and return a pointer to that command. Return a NULL pointer if NAME isn't a command name. */ COMMAND * find_command (name) char *name; { register int i; for (i = 0; commands[i].name; i++) if (strcmp (name, commands[i].name) == 0) return (&commands[i]); return ((COMMAND *)NULL); } /* Strip whitespace from the start and end of STRING. Return a pointer into STRING. */ char * stripwhite (string) char *string; { register char *s, *t; for (s = string; whitespace (*s); s++) ; if (*s == 0) return (s); t = s + strlen (s) - 1; while (t > s && whitespace (*t)) t--; *++t = '\0'; return s; } /* **************************************************************** */ /* */ /* Interface to Readline Completion */ /* */ /* **************************************************************** */ char *command_generator (); char **fileman_completion (); /* Tell the GNU Readline library how to complete. We want to try to complete on command names if this is the first word in the line, or on filenames if not. */ initialize_readline () { /* Allow conditional parsing of the ~/.inputrc file. */ rl_readline_name = "FileMan"; /* Tell the completer that we want a crack first. */ rl_attempted_completion_function = (CPPFunction *)fileman_completion; } /* Attempt to complete on the contents of TEXT. START and END bound the region of rl_line_buffer that contains the word to complete. TEXT is the word to complete. We can use the entire contents of rl_line_buffer in case we want to do some simple parsing. Return the array of matches, or NULL if there aren't any. */ char ** fileman_completion (text, start, end) char *text; int start, end; { char **matches; matches = (char **)NULL; /* If this word is at the start of the line, then it is a command to complete. Otherwise it is the name of a file in the current directory. */ if (start == 0) matches = completion_matches (text, command_generator); return (matches); } /* Generator function for command completion. STATE lets us know whether to start from scratch; without any state (i.e. STATE == 0), then we start at the top of the list. */ char * command_generator (text, state) char *text; int state; { static int list_index, len; char *name; /* If this is a new word to complete, initialize now. This includes saving the length of TEXT for efficiency, and initializing the index variable to 0. */ if (!state) { list_index = 0; len = strlen (text); } /* Return the next name which partially matches from the command list. */ while (name = commands[list_index].name) { list_index++; if (strncmp (name, text, len) == 0) return (dupstr(name)); } /* If no names matched, then return NULL. */ return ((char *)NULL); } /* **************************************************************** */ /* */ /* FileMan Commands */ /* */ /* **************************************************************** */ /* String to pass to system (). This is for the LIST, VIEW and RENAME commands. */ static char syscom[1024]; /* List the file(s) named in arg. */ com_list (arg) char *arg; { if (!arg) arg = ""; sprintf (syscom, "ls -FClg %s", arg); return (system (syscom)); } com_view (arg) char *arg; { if (!valid_argument ("view", arg)) return 1; sprintf (syscom, "more %s", arg); return (system (syscom)); } com_rename (arg) char *arg; { too_dangerous ("rename"); return (1); } com_stat (arg) char *arg; { struct stat finfo; if (!valid_argument ("stat", arg)) return (1); if (stat (arg, &finfo) == -1) { perror (arg); return (1); } printf ("Statistics for '%s':\n", arg); printf ("%s has %d link%s, and is %d byte%s in length.\n", arg, finfo.st_nlink, (finfo.st_nlink == 1) ? "" : "s", finfo.st_size, (finfo.st_size == 1) ? "" : "s"); printf ("Inode Last Change at: %s", ctime (&finfo.st_ctime)); printf (" Last access at: %s", ctime (&finfo.st_atime)); printf (" Last modified at: %s", ctime (&finfo.st_mtime)); return (0); } com_delete (arg) char *arg; { too_dangerous ("delete"); return (1); } /* Print out help for ARG, or for all of the commands if ARG is not present. */ com_help (arg) char *arg; { register int i; int printed = 0; for (i = 0; commands[i].name; i++) { if (!*arg || (strcmp (arg, commands[i].name) == 0)) { printf ("%s\t\t%s.\n", commands[i].name, commands[i].doc); printed++; } } if (!printed) { printf ("No commands match '%s'. Possibilties are:\n", arg); for (i = 0; commands[i].name; i++) { /* Print in six columns. */ if (printed == 6) { printed = 0; printf ("\n"); } printf ("%s\t", commands[i].name); printed++; } if (printed) printf ("\n"); } return (0); } /* Change to the directory ARG. */ com_cd (arg) char *arg; { if (chdir (arg) == -1) { perror (arg); return 1; } com_pwd (""); return (0); } /* Print out the current working directory. */ com_pwd (ignore) char *ignore; { char dir[1024], *s; s = getwd (dir); if (s == 0) { printf ("Error getting pwd: %s\n", dir); return 1; } printf ("Current directory is %s\n", dir); return 0; } /* The user wishes to quit using this program. Just set DONE non-zero. */ com_quit (arg) char *arg; { done = 1; return (0); } /* Function which tells you that you can't do this. */ too_dangerous (caller) char *caller; { fprintf (stderr, "%s: Too dangerous for me to distribute. Write it yourself.\n", caller); } /* Return non-zero if ARG is a valid argument for CALLER, else print an error message and return zero. */ int valid_argument (caller, arg) char *caller, *arg; { if (!arg || !*arg) { fprintf (stderr, "%s: Argument required.\n", caller); return (0); } return (1); }
Concept Index
i r
Function and Variable Index
a b
- backward-char (C-b)
- backward-delete-char (Rubout)
- backward-kill-line (C-x Rubout)
- backward-kill-word (M-DEL
- backward-word (M-b)
- beginning-of-history (M-<)
- beginning-of-line (C-a)
- bell-style
- call-last-kbd-macro (C-x e)
- capitalize-word (M-c)
- character-search (C-])
- character-search-backward (M-C-])
- clear-screen (C-l)
- comment-begin
- complete (TAB)
- completion-query-items
- completion_matches
- convert-meta
- copy-backward-word ()
- copy-forward-word ()
- copy-region-as-kill ()
- delete-char (C-d)
- delete-horizontal-space ()
- digit-argument (M-0, M-1, ... M--)
- digit_p
- digit_value
- ding
- disable-completion
- do-uppercase-version (M-a, M-b, M-x, ...)
- downcase-word (M-l)
- dump-functions ()
- dump-macros ()
- dump-variables ()
- editing-mode
- enable-keypad
- end-kbd-macro (C-x ))
- end-of-history (M->)
- end-of-line (C-e)
- exchange-point-and-mark (C-x C-x)
- expand-tilde
- filename_completion_function
- forward-char (C-f)
- forward-search-history (C-s)
- forward-word (M-f)
- free_undo_list
- next-history (C-n)
- non-incremental-forward-search-history (M-n)
- non-incremental-reverse-search-history (M-p)
- numeric
- re-read-init-file (C-x C-r)
- readline
- redraw-current-line ()
- reverse-search-history (C-r)
- revert-line (M-r)
- rl_add_defun
- rl_add_undo
- rl_attempted_completion_function
- rl_basic_quote_characters
- rl_basic_word_break_characters
- rl_begin_undo_group
- rl_bind_key
- rl_bind_key_in_map
- rl_binding_keymap
- rl_callback_handler_install
- rl_callback_handler_remove
- rl_callback_read_char
- rl_char_is_quoted_p
- rl_clear_message
- rl_complete
- rl_complete_internal
- rl_completer_quote_characters
- rl_completer_word_break_characters
- rl_completion_append_character
- rl_completion_entry_function
- rl_completion_query_items
- rl_copy_keymap
- rl_copy_text
- rl_delete_text
- rl_directory_completion_hook
- rl_discard_keymap
- rl_do_undo
- rl_done
- rl_end
- rl_end_undo_group
- rl_event_hook
- rl_executing_keymap
- rl_extend_line_buffer
- rl_filename_completion_desired
- rl_filename_dequoting_function
- rl_filename_quote_characters
- rl_filename_quoting_desired
- rl_filename_quoting_function
- rl_forced_update_display
- rl_function_dumper
- rl_function_of_keyseq
- rl_generic_bind
- rl_get_keymap
- rl_get_keymap_by_name
- rl_get_keymap_name
- rl_getc
- rl_getc_function
- rl_ignore_completion_duplicates
- rl_ignore_some_completions_function
- rl_inhibit_completion
- rl_initialize
- rl_insert_completions
- rl_insert_text
- rl_instream
- rl_invoking_keyseqs
- rl_invoking_keyseqs_in_map
- rl_kill_text
- rl_library_version
- rl_line_buffer
- rl_list_funmap_names
- rl_make_bare_keymap
- rl_make_keymap
- rl_mark
- rl_message
- rl_modifying
- rl_named_function
- rl_on_new_line
- rl_outstream
- rl_parse_and_bind
- rl_pending_input
- rl_point
- rl_possible_completions
- rl_prompt
- rl_read_init_file
- rl_read_key
- rl_readline_name
- rl_redisplay
- rl_redisplay_function
- rl_reset_line_state
- rl_reset_terminal
- rl_set_keymap
- rl_special_prefixes
- rl_startup_hook
- rl_stuff_char
- rl_terminal_name
- rl_unbind_command_in_map
- rl_unbind_function_in_map
- rl_unbind_key
- rl_unbind_key_in_map