Copyright Thomas Leonard and others, 2013

Zero Install is a decentralised cross-distribution software installation system available under the LGPL. It allows software developers to publish programs directly from their own web-sites, while supporting features familiar from centralised distribution repositories such as shared libraries, automatic updates and digital signatures. It is intended to complement, rather than replace, the operating system's package management. 0install packages never interfere with those provided by the distribution.

0install does not define a new packaging format; unmodified tarballs or zip archives can be used. Instead, it defines an XML metadata format to describe these packages and the dependencies between them. A single metadata file can be used on multiple platforms (e.g. Ubuntu, Debian, Fedora, openSUSE, Mac OS X and Windows), assuming binary or source archives are available that work on those systems.

0install also has some interesting features not often found in traditional package managers. For example, while it will share libraries whenever possible, it can always install multiple versions of a package in parallel when there are conflicting requirements. Installation is always side-effect-free (each package is unpacked to its own directory and will not touch shared directories such as /usr/bin), making it ideal for use with sandboxing technologies and virtualisation.

The XML file describing the program's requirements can also be included in a source-code repository, allowing full dependency handling for unreleased developer versions. For example, a user can clone a Git repository and build and test the program, automatically downloading newer versions of libraries where necessary, without interfering with the versions of those libraries installed by their distribution, which continue to be used for other software.

See the 0install.net web-site for full details.

0install is written in a mixture of Python and OCaml. You will need the OCaml build tools and some OCaml libraries to compile 0install. On Debian use:

$ sudo apt-get install gettext ocaml-nox ocaml-findlib libyojson-ocaml-dev \
   libxmlm-ocaml-dev camlp4-extra make liblwt-ocaml-dev libounit-ocaml-dev \
   python-gobject libextlib-ocaml-dev libcurl-ocaml-dev libssl-ocaml-dev

You can also get the dependencies using OPAM:

$ opam sw 4.00.1
$ eval `opam config env`
$ opam install yojson xmlm ounit lwt extlib ssl ocurl

In the top-level directory, run:

$ make && sudo make install

You can also install just to your home directory (this doesn't require root access):

$ make && make install_home
$ export PATH=$HOME/bin:$PATH

Logging out and back in again will ensure $PATH and the Applications menu get updated correctly, on Ubuntu at least.

To try 0install without installing:

$ make
$ ./dist/files/0install --help

A Windows binary of 0install is available at 0install.de.

Warning: I know very little about Windows. These instructions are the result of many hours of random trial-and-error and Google searches. Please help improve things here if you can.

If you want to compile from source on Windows you'll need to install quite a few things manually:

• OCaml 4.0.1 Windows Installer
• Cygwin and various of its packages: mingw64-i686-gcc-core, mingw-i686-headers and make, at least (make sure /cygdrive/c/MinGW/bin is in $PATH)
• Xmlm
• [Yojson] (http://mjambon.com/yojson.html) (and its dependencies: Cppo, Easy-format, Biniou)
• Lwt (and its dependency React). You'll also need to apply this EPIPE fix
• extlib - if you get "ocamlfind: extLib.lib: No such file or directory", modify install.ml to use the "Unix" extensions for "Win32" too.
• openssl
  1. Use cp -Lr openssl copy to turn all symlinks into regular files.
  2. perl Configure mingw shared --prefix=C:/OCaml in copy.
  3. cp -Lr copy copy2 to turn all symlinks into regular files again.
  4. make and make install inside copy2.
• ocaml-ssl - use ./configure LDFLAGS=-LC:/OCaml/lib CFLAGS=-IC:/OCaml/include.
• libcurl:
  1. Edit each Makefile.m32 to say OPENSSL_PATH = c:/OCaml.
  2. Build with mingw32-make.exe mingw32-ssl.
  3. Copy lib/libcurl.a to c:/OCaml/lib.
• ocurl - these steps worked for me:

  1. There's no curl-config, so edit configure to use:

         CURLDIR=-Ic:/OCaml/lib
         CURLFLAGS="-lcurl -ccopt -lssl -ccopt -lcrypto -ccopt -lwldap32"
         CURLLIBS=
     
         CFLAGS="$CURLDIR -DCURL_STATICLIB -Ic:/OCaml/include"
     

  2. ./configure

  3. Edit Makefile to set FINDLIB = ocamlfind.

  4. curl.h seems to redefine interface, so rename all ocurrances in curl-helper.c to interface_.

  5. make and make install.

Then, to build 0install under Cygwin:

cd ocaml
make

This creates the executables build/ocaml/install.exe and build/ocaml/0install-runenv.exe. If you'd like to make the top-level Makefile work on Windows so you can "make install", please send a patch.

A bash completion script is available in share/bash-completion. It can be sourced from your .bashrc or added under /usr/share/bash-completion. Note that you may have to install a separate "bash-completion" package on some systems.

For zsh users, copy the script in share/zsh/site-functions/ to a directory in your $fpath (e.g. /usr/local/share/zsh/site-functions).

For fish-shell users, add the full path to share/fish/completions to $fish_complete_path.

These completion scripts are installed automatically by "make install".

To install Edit and name it 'rox-edit':

$ 0install add rox-edit http://rox.sourceforge.net/2005/interfaces/Edit

To run it (use the name you chose above):

$ rox-edit

When you run it, 0install will check how long it has been since it checked for updates and will run a check in the background if it has been too long. To check for updates manually:

$ 0install update rox-edit
http://rox.sourceforge.net/2005/interfaces/ROX-Lib: 2.0.5 -> 2.0.6

This shows that ROX-Lib, a library rox-edit uses, was upgraded.

If an upgrade stops a program from working, use "0install whatchanged". This will tell you when the application was last upgraded and what changed, and tell you how to revert to the previous version:

$ 0install whatchanged rox-edit
Last checked    : Tue Sep 25 09:45:19 2012
Last update     : 2012-09-25
Previous update : 2012-08-25

http://rox.sourceforge.net/2005/interfaces/ROX-Lib: 2.0.5 -> 2.0.6

To run using the previous selections, use:
0install run /home/tal/.config/0install.net/apps/rox-edit/selections-2012-08-25.xml

To see where things have been stored:

$ 0install select rox-edit
- URI: http://rox.sourceforge.net/2005/interfaces/Edit
  Version: 2.2
  Path: /home/tal/.cache/0install.net/implementations/sha256=ba3b4953...c8ce3177f08c926bebafcf16b9
  - URI: http://rox.sourceforge.net/2005/interfaces/ROX-Lib
    Version: 2.0.6
    Path: /home/tal/.cache/0install.net/implementations/sha256=ccefa7b187...16b6d0ad67c4df6d0c06243e
  - URI: http://repo.roscidus.com/python/python
    Version: 2.7.3-4
    Path: (package:deb:python2.7:2.7.3-4:x86_64)

To view or change configuration settings:

$ 0install config

For more information, see the man-page for 0install and the 0install.net web-site.

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

Please report any bugs to the mailing list.