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.
		
	
			
		
			
				
	
	
		
			37 lines
		
	
	
	
		
			893 B
		
	
	
	
		
			Text
		
	
	
	
	
	
			
		
		
	
	
			37 lines
		
	
	
	
		
			893 B
		
	
	
	
		
			Text
		
	
	
	
	
	
#! @shell@ -e
 | 
						|
 | 
						|
url=$1
 | 
						|
 | 
						|
if test -z "$url"; then
 | 
						|
    echo "syntax: nix-prefetch-url URL" >&2
 | 
						|
    exit 1
 | 
						|
fi
 | 
						|
 | 
						|
# !!! race? should be relatively safe, `svn export' barfs if $tmpPath exists.
 | 
						|
tmpPath1=@storedir@/nix-prefetch-url-$$
 | 
						|
 | 
						|
# Perform the checkout.
 | 
						|
@curl@ --fail --location --max-redirs 20 "$url" > $tmpPath1
 | 
						|
 | 
						|
# Compute the hash.
 | 
						|
hash=$(@bindir@/nix-hash --flat $tmpPath1)
 | 
						|
echo "hash is $hash" >&2
 | 
						|
 | 
						|
# Rename it so that the fetchsvn builder can find it.
 | 
						|
tmpPath2=@storedir@/nix-prefetch-url-$hash
 | 
						|
test -e $tmpPath2 || mv $tmpPath1 $tmpPath2 # !!! race
 | 
						|
 | 
						|
# Create a Nix expression that does a fetchsvn.
 | 
						|
storeExpr=$( \
 | 
						|
  echo "(import @datadir@/nix/corepkgs/fetchurl) \
 | 
						|
        {url = $url; md5 = \"$hash\"; system = \"@system@\";}" \
 | 
						|
  | nix-instantiate -)
 | 
						|
 | 
						|
# Realise it.
 | 
						|
finalPath=$(nix-store -qnB --force-realise $storeExpr)
 | 
						|
 | 
						|
echo "path is $finalPath" >&2
 | 
						|
 | 
						|
rm -rf $tmpPath2 || true
 | 
						|
 | 
						|
echo $hash
 |