This is the AT&T Software Technology ast software download site from AT&T Research. The AT&T AST OpenSource Software Collection provides an overview and Practical Reusable UNIX Software provides a historical perspective. You can join the ast and uwin mailgroups, or monitor the mail archives. There is also an AT&T internal talk. The man page inde…
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Latest commit 77b7513 Feb 22, 2018
siteshwar Set ucb universe as default
echo builtin should behave berkley style by default.
Resolves: #370


This repository contains the AT&T Software Technology (AST) toolkit from AT&T Research. As of November 2017 the development focus has been shifted to the ksh (or ksh93) command and supporting code required to build it.

The non-ksh code of the AST project is no longer being actively maintained. If you are interested in the non-ksh code see below for details on which branches contain the full AST code base.

Building Korn shell

Building ksh requires the Meson build system. To build ksh execute these commands from the project root directory:

meson build
ninja -C build

You can add a --prefix flag followed by a path to the meson build command to specify where the binaries and libraries are installed. The default is /usr/local.


The ksh executable, helper libraries and man page can be installed with:

ninja -C build install

Getting KornShell


Latest builds for Red Hat Enterprise Linux (CentOS) and Fedora can be found in copr.

TBD packages for other Linux distros.





Contributing changes to the source code

See the contributing guidelines for information about code style, unit tests, and other topics of interest to anyone who wants to modify the source.

Working with the full AST source

Full AST source code is available under the 2012-08-01-master and 2016-01-10-beta branches (see below for more details). Bug fixes to these branches are welcome but they are otherwise under low maintenance.

The full AST code includes many tools and libraries, like KSH, NMAKE, SFIO, VMALLOC, VCODEX, etc. It also includes efficient replacements for a lot of the POSIX tools. It was designed to be portable across many UNIX systems and also works under UWIN on Microsoft Windows (see UWIN repo on GitHub under att/uwin).

This software is used to build itself, using NMAKE. After cloning this repo, cd to the top directory of it and run:

./bin/package make

NOTE: That build command only applies to the legacy branches that include the entire AST source. It does not apply to the current master branch that is focused solely on the ksh command and uses the Meson build system.

Almost all the tools in this package (including the bin/package script are self-documenting; run --man (or --html) for the man page for the tool.

(If you were used to the old AST packaging mechanism, on, this repo is equivalent to downloading the INIT and ast-open packages and running: ./bin/package read on them).


The master branch contains the current development version of ksh93. It only contains source code for ksh93 and the libraries required to build it.

The 2012-08-01-master branch contains the the last stable release of full AST source code. It contains one cherry-picked change to allow building on Linux.

The 2016-01-10-beta branch contains the last beta release of full AST source code plus a number of patches that were later added on top of it. Changes for the legacy AST project are normally merged to this branch.

The gh-pages branch will probably be removed. It contains files needed to generate the static AST project page hosted by Github. See for more info.


This section needs more detail and clarity. The original README document said the following:

Each package is covered by one of the license files


where is the license type for the package. At the top of each license file is a URL; the license covers all software that refers to this URL. For details run

bin/package license []

Any archives, distributions or packages made from source or binaries covered by license(s) must contain the corresponding license file(s).

Contact Us

The primary mechanism for interacting with this project is the Github project by opening issues and pull-requests and watching the project.


Use #ksh channel on freenode to discuss about AT&T KornShell and related variants.

TBD is setting up a public Gitter, and other channels for real-time communication.

Archives of the legacy AST mailing lists (which is mostly about ksh) can be read at and These mailing lists now receive almost zero traffic. It no longer appears to be possible to subscribe to those mailing lists.