The Zero Install Injector makes it easy for users to install software
without needing root privileges. It takes the URL of a program and
runs it (downloading it first if necessary). Any dependencies of the
program are fetched in the same way. The user controls which version
of the program and its dependencies to use.
Zero Install is a decentralized installation system (there is no
central repository; all packages are identified by URLs),
loosely-coupled (if different programs require different versions of a
library then both versions are installed in parallel, without
conflicts), and has an emphasis on security (all package descriptions
are GPG-signed, and contain cryptographic hashes of the contents of
each version). Each version of each program is stored in its own
sub-directory within the Zero Install cache (nothing is installed to
directories outside of the cache, such as /usr/bin) and no code from
the package is run during install or uninstall. The system can
automatically check for updates when software is run.