* `nix-store --read-log / -l PATH' shows the build log of PATH, if

available.  For instance,

    $ nix-store -l $(which svn) | less

  lets you read the build log of the Subversion instance in your
  profile.

* `nix-store -qb': if applied to a non-derivation, take the deriver.

src/libstore/build.cc

@@ -1511,7 +1511,7 @@ void DerivationGoal::computeClosure()
 }
 
 
-static string drvsLogDir = "drvs";
+string drvsLogDir = "drvs";
 
 
 void DerivationGoal::openLogFile()

src/libstore/build.hh

@@ -8,6 +8,9 @@
 namespace nix {
 
     
+extern string drvsLogDir;
+
+
 /* Ensure that the output paths of the derivation are valid.  If they
    are already valid, this is a no-op.  Otherwise, validity can
    be reached in two ways.  First, if the output paths have