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.
* Fixed a segfault caused by the buffering of stderr.
* Fix now allows the specification of the full output path. This
should be used with great care, since it by-passes the normal hash
generation.
* Incremented the version number to 0.4 (prerelease).
substituting for (obvious, really).
* For greater efficiency, nix-pull/unnar will place the output in a
path that is probably the same as what is actually needed, thus
preventing a path copy.
* Even if a output id is given in a Fix package expression, ensure
that the resulting Nix derive expression has a different id. This
is because Nix expressions that are semantically equivalent (i.e.,
build the same result) might be different w.r.t. efficiency or
divergence. It is absolutely vital for the substitute mechanism
that such expressions are not used interchangeably.
value; this potentially dangerous feature enables better
sharing for those paths for which the content is known in
advance (e.g., because a content hash is given).
* Fast builds: if we can expand all output paths of a derive
expression, we don't have to build.
number of bytes, e.g., in case of a signal like SIGSTOP.
This caused `nix --dump' to fail sometimes.
Note that this bug went unnoticed because the call to `nix
--dump' is in a pipeline, and the shell ignores non-zero
exit codes from all but the last element in the pipeline.
Is there any way to check the result of the initial elements
in the pipeline? (In other words, is it at all possible to
write reliable shell scripts?)
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.
