Linenoise Next Generation

A small, portable GNU readline replacement for Linux, Windows and MacOS which is capable of handling UTF-8 characters. Unlike GNU readline, which is GPL, this library uses a BSD license and can be used in any kind of program.

Origin

This linenoise implementation is based on the work by Salvatore Sanfilippo and 10gen Inc. The goal is to create a zero-config, BSD licensed, readline replacement usable in Apache2 or BSD licensed programs.

Features

single-line and multi-line editing mode with the usual key bindings implemented
history handling
completion
BSD license source code
Only uses a subset of VT100 escapes (ANSI.SYS compatible)
UTF8 aware
support for Linux, MacOS and Windows

It deviates from Salvatore's original goal to have a minimal readline replacement for the sake of supporting UTF8 and Windows. It deviates from 10gen Inc.'s goal to create a C++ interface to linenoise. This library uses C++ internally, but to the user it provides a pure C interface that is compatible with the original linenoise API. C interface.

Requirements

To build this library, you will need a C++11-enabled compiler and some recent version of CMake.

Build instructions

To build this library on Linux, first create a build directory

mkdir -p build

and then build the library:

(cd build && cmake -DCMAKE_BUILD_TYPE=Release .. && make)

To build and install the library at the default target location, use

(cd build && cmake -DCMAKE_BUILD_TYPE=Release .. && make && sudo make install)

The default installation location can be adjusted by setting the DESTDIR variable when invoking make install:

(cd build && make DESTDIR=/tmp install)

To build the library on Windows, use these commands in an MS-DOS command prompt:

md build
cd build

After that, invoke the appropriate command to create the files for your target environment:

32 bit: cmake -G "Visual Studio 12 2013" -DCMAKE_BUILD_TYPE=Release ..
64 bit: cmake -G "Visual Studio 12 2013 Win64" -DCMAKE_BUILD_TYPE=Release ..

After that, open the generated file linenoise.sln from the build subdirectory with Visual Studio.

note: the following sections of the README.md are from the original linenoise repository and are partly outdated

Can a line editing library be 20k lines of code?

Line editing with some support for history is a really important feature for command line utilities. Instead of retyping almost the same stuff again and again it's just much better to hit the up arrow and edit on syntax errors, or in order to try a slightly different command. But apparently code dealing with terminals is some sort of Black Magic: readline is 30k lines of code, libedit 20k. Is it reasonable to link small utilities to huge libraries just to get a minimal support for line editing?

So what usually happens is either:

Large programs with configure scripts disabling line editing if readline is not present in the system, or not supporting it at all since readline is GPL licensed and libedit (the BSD clone) is not as known and available as readline is (Real world example of this problem: Tclsh).
Smaller programs not using a configure script not supporting line editing at all (A problem we had with Redis-cli for instance).

The result is a pollution of binaries without line editing support.

So Salvatore spent more or less two hours doing a reality check resulting in this little library: is it really needed for a line editing library to be 20k lines of code? Apparently not, it is possibe to get a very small, zero configuration, trivial to embed library, that solves the problem. Smaller programs will just include this, supporing line editing out of the box. Larger programs may use this little library or just checking with configure if readline/libedit is available and resorting to linenoise if not.

Terminals, in 2010.

Apparently almost every terminal you can happen to use today has some kind of support for basic VT100 escape sequences. So Salvatore tried to write a lib using just very basic VT100 features. The resulting library appears to work everywhere Salvatore tried to use it, and now can work even on ANSI.SYS compatible terminals, since no VT220 specific sequences are used anymore.

The original library has currently about 1100 lines of code. In order to use it in your project just look at the example.c file in the source distribution, it is trivial. Linenoise is BSD code, so you can use both in free software and commercial software.

Tested with...

Linux text only console ($TERM = linux)
Linux KDE terminal application ($TERM = xterm)
Linux xterm ($TERM = xterm)
Linux Buildroot ($TERM = vt100)
Mac OS X iTerm ($TERM = xterm)
Mac OS X default Terminal.app ($TERM = xterm)
OpenBSD 4.5 through an OSX Terminal.app ($TERM = screen)
IBM AIX 6.1
FreeBSD xterm ($TERM = xterm)
ANSI.SYS
Emacs comint mode ($TERM = dumb)
Windows

Please test it everywhere you can and report back!

Let's push this forward!

Patches should be provided in the respect of linenoise sensibility for small and easy to understand code that and the license restrictions. Extensions must be submitted under a BSD license-style. A contributor license is required for contributions.

jbenden / linenoise-ng