editline/man/editline.3

.TH EDITLINE 3
.SH NAME
editline \- command-line editing library with history
.SH SYNOPSIS
.nf
.B "char *readline(char *prompt);"
.fi
.SH DESCRIPTION
.I Editline
is a library that provides an line-editing interface with history.
It is intended to be functionally equivalent with the
.I readline
library provided by the Free Software Foundation, but much smaller.
The bulk of this manual page describes the user interface.
.PP
The
.I readline()
function displays the given
.I prompt
on stdout, waits for user input on stdin and then
returns a line of text with the trailing newline removed.  The data is returned in a
buffer allocated with
.IR malloc (3),
so the space should be released with
.IR free (3)
when the calling program is done with it.
.PP
Each line returned is copied to the internal history list, unless it happens
to be equal to the previous line.  This is configurable if you are building editline
from source.
.SS User Interface
A program that uses this library provides a simple emacs-like editing interface to
its users.  A line may be edited before it is sent to the calling program by typing
either control characters or escape sequences.  A control character, shown as a caret
followed by a letter, is typed by holding down the ``control'' key while the letter
is typed.  For example, ``^A'' is a control-A.  An escape sequence is entered by
typing the ``escape'' key followed by one or more characters.  The escape key is
abbreviated as ``ESC''.  Note that unlike control keys, case matters in escape
sequences; ``ESC\ F'' is not the same as ``ESC\ f''.
.PP
An editing command may be typed anywhere on the line, not just at the beginning.  In
addition, a return may also be typed anywhere on the line, not just at the end.
.PP
Most editing commands may be given a repeat count,
.IR n ,
where
.I n
is a number.
To enter a repeat count, type the escape key, the number, and then
the command to execute.
For example, ``ESC\ 4\ ^f'' moves forward four characters.
If a command may be given a repeat count then the text ``[n]'' is given at the
end of its description.
.PP
The following control characters are accepted:
.RS
.nf
.ta \w'ESC DEL  'u
^A	Move to the beginning of the line
^B	Move left (backwards) [n]
^D	Delete character [n]
^E	Move to end of line
^F	Move right (forwards) [n]
^G	Ring the bell
^H	Delete character before cursor (backspace key) [n]
^I	Complete filename (tab key); see below
^J	Done with line (return key)
^K	Kill to end of line (or column [n])
^L	Redisplay line
^M	Done with line (alternate return key)
^N	Get next line from history [n]
^P	Get previous line from history [n]
^R	Search backward (forward if [n]) through history for
\&	text; must start line if text begins with an uparrow
^T	Transpose characters
^V	Insert next character, even if it is an edit command
^W	Wipe to the mark
^X^X	Exchange current location and mark
^Y	Yank back last killed text
^[	Start an escape sequence (escape key)
^]c	Move forward to next character ``c''
^?	Delete character before cursor (delete key) [n]
.fi
.RE
.PP
The following escape sequences are provided.
.RS
.nf
.ta \w'ESC DEL  'u
ESC\ ^H	Delete previous word (backspace key) [n]
ESC\ DEL	Delete previous word (delete key) [n]
ESC\ SP	Set the mark (space key); see ^X^X and ^Y above
ESC\ \.	Get the last (or [n]'th) word from previous line
ESC\ ?	Show possible completions; see below
ESC\ <	Move to start of history
ESC\ >	Move to end of history
ESC\ b	Move backward a word [n]
ESC\ d	Delete word under cursor [n]
ESC\ f	Move forward a word [n]
ESC\ l	Make word lowercase [n]
ESC\ m	Toggle if 8bit chars display normally or with an
\&	``M\-'' prefix
ESC\ u	Make word uppercase [n]
ESC\ y	Yank back last killed text
ESC\ v	Show library version
ESC\ w	Make area up to mark yankable
ESC\ nn	Set repeat count to the number nn
ESC\ C	Read from environment variable ``_C_'', where C is
\&	an uppercase letter
.fi
.RE
.PP
The
.I editline
library has a small macro facility.
If you type the escape key followed by an uppercase letter,
.IR C ,
then the contents of the environment variable
.I _C_
are read in as if you had typed them at the keyboard.
For example, if the variable
.I _L_
contains the following:
.PP
.RS
^A^Kecho '^V^[[H^V^[[2J'^M
.RE
.PP
Then typing ``ESC L'' will move to the beginning of the line, kill the
entire line, enter the echo command needed to clear the terminal (if your
terminal is like a VT-100), and send the line back to the shell.
.PP
The
.I editline
library also does filename completion.
Suppose the root directory has the following files in it:
.PP
.RS
.nf
.ta \w'core   'u
bin	vmunix
core	vmunix.old
.fi
.RE
.PP
If you type ``rm\ /v'' and then the tab key.
.I Editline
will then finish off as much of the name as possible by adding ``munix''.
Because the name is not unique, it will then beep.
If you type the escape key and a question mark, it will display the
two choices.
If you then type a period and a tab, the library will finish off the filename
for you:
.PP
.RS
.nf
.RI "rm /v[TAB]" munix ".[TAB]" old
.fi
.RE
.PP
The tab key is shown by ``[TAB]'' and the automatically-entered text
is shown in italics.
.SH USAGE
To include
.I readline()
in your program, simply call it as you do any other function. Just make sure to link
your program with libeditline.
.SS Example
The following brief example lets you enter a line and edit it, then displays it.
.nf
.B ""
.B #include <stdlib.h>
.B ""
.B extern char *readline(char *prompt);
.B ""
.B int main (void)
.B {
.RS
.B     char *p;
.B ""
.B     while ((p = readline("CLI>"))) {
.RS
.B         puts(p);
.B         free(p);
.RE
.B     }
.B ""
.B     return 0;
.RE
.B }
.fi
.SH BUGS AND LIMITATIONS
Does not handle multiple lines or unicode characters well.  See the TODO
file in the distribution if you want to help out.
.SH AUTHORS
The original editline library was created by Simmule R. Turner and Rich
$alz.  It now exists in several forks: Heimdal, Festival speech tools,
Mozilla, Google Gadgets for Linux, and many other places.  The original
manual page was made by David W. Sanderson.  Currently maintained by
Joachim Nilsson at http://github.com/troglobit/editline