Nix expressions.
To subscribe to a channel (needs to be done only once):
nix-channel --add \
http://catamaran.labs.cs.uu.nl/dist/nix/channels/nixpkgs-unstable
This just adds the given URL to ~/.nix-channels (which can also be
edited manually).
To update from all channels:
nix-channel --update
This fetches the latest expressions and pulls cache manifests. The
default Nix expression (~/.nix-defexpr) is made to point to the
conjunction of the expressions downloaded from all channels.
So to update all installed derivations in the current user
environment:
nix-channel --update
nix-env --upgrade '*'
If you are really courageous, you can put this in a cronjob or
something.
You can subscribe to multiple channels. It is not entirely clear
what happens when there are name clashes between derivations from
different channels. From nix-env/main.cc it appears that the one
with the lowest (highest?) hash will be used, which is pretty
meaningless.
The script nix-install-package takes a `Nix package file' (which
contains one or more derivations, along with URLs of Nix caches),
unpacks it, pulls the caches, and installs the derivations in the
user's environment.
For best results, associate the command `xterm -e
/nix/bin/nix-install-package' with the MIME type
`application/x-nix-package' and visit
http://losser.st-lab.cs.uu.nl/~eelco/test/.
hash for which no local expansion is available, Nix can execute a
`substitute' which should produce a path with such a hash.
This is policy-free since Nix does not in any way specify how the
substitute should work, i.e., it's an arbitrary (unnormalised)
fstate expression. For example, `nix-pull' registers substitutes
that fetch Nix archives from the network (through `wget') and unpack
them, but any other method is possible as well. This is an
improvement over the old Nix sharing scheme, which had a policy
(fetching through `wget') built in.
The sharing scheme doesn't work completely yet because successors
from fstate rewriting have to be registered on the receiving side.
Probably the whole successor stuff can be folded up into the
substitute mechanism; this would be a nice simplification.
archives (using the package in corepkgs/nar).
* queryPathByHash -> expandHash, and it takes an argument specifying
the target path (which may be empty).
* Install the core Fix packages in $prefix/share/fix. TODO: bootstrap
Nix and install Nix as a Fix package.
a mapping from the hash to a url has been registered through `nix
regurl'.
* Bug fix in nix: don't pollute stdout when running tar, it made
nix-switch barf.
* Bug fix in nix-push-prebuilts: don't create a subdirectory on the
target when rsync'ing.
sharing package directories (i.e., the result of building a Nix
descriptor).
`nix-pull-prebuilts' obtains a list of all known prebuilts by
consulting the paths and URLs specified in
$prefix/etc/nix/prebuilts.conf. The mappings ($pkghash,
$prebuilthash) and ($prebuilthash, $location) are registered with
Nix so that it can use the prebuilt with hash $prebuilthash when
installing a package with hash $pkghash by downloading and unpacking
$location.
`nix-push-prebuilts' creates prebuilts for all packages for which no
prebuilt is known to exist. It can then optionally upload these
to the network through rsync.
`nix-[pull|push]-prebuilts' just provide a policy. Nix provides the
mechanism through the `nix [export|regprebuilt|regurl]' commands.
doesn't actually delete any packages, it just prints their
descriptor hashes. So we can do
nix info $(nix-collect-garbage)
to print out the ids of the packages that would be deleted, and
nix delpkg $(nix-collect-garbage)
to actually delete them.
build action for `system' packages (like system.fix) that have
dependencies on all packages we want to activate.
So the command sequence to switch to a new activation configuration
of the system would be:
$ fix -i .../fixdescriptors/system.fix
...
system.fix -> 89cf4713b37cc66989304abeb9ea189f
$ nix-switch 89cf4713b37cc66989304abeb9ea189f
* A nix-profile.sh script that can be included in .bashrc.
Eelco Dolstra