user5490: I'm preparing the Plutus Pioneer program and installing the environment.
After installing nix and updating the "IOHK binary cache", I tried to do nix build but it seems that it is building and compiling ghc as shown below and it takes a very long time.
MyMac$ nix build -f default.nix plutus.haskell.packages.plutus-core
trace: To materialize project.plan-nix for Agda entirely, pass a writable path as the `materialized` argument and run the 'updateMaterialized' script in 'passthru'.
[1/1/619 built] building ghc-8.6.5 (buildPhase): clang-7: warning: argument unu

Current nix.conf
substituters        = https://hydra.iohk.io https://iohk.cachix.org https://cache.nixos.org/
trusted-public-keys = hydra.iohk.io:f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ= iohk.cachix.org-1:DpRUyj7h7V830dp/i6Nti+NEO2/nhblbov/8MW7Rqoo= cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=

sandbox = true
extra-sandbox-paths = /System/Library/Frameworks /System/Library/PrivateFrameworks /usr/lib /private/tmp /private/var/tmp /usr/bin/env
extra-experimental-features = nix-command
build-users-group = nixbld

I found the following warning message:

If you want to use Nix with this project, make sure to set up the IOHK
binary cache. If you do not do this, you will end up building GHC,
which takes several hours. If you find yourself building GHC, STOP and
fix the cache.

Could you guide me how I can fix the cache?
Thanks in advance.

user6092: It may be the case that you edited your nix.conf file after you launched nix-daemon.
You would need to kill and start the daemon again to pick up the updated nix.conf:

$ sudo pkill nix-daemon

and then

$ sudo nix-daemon &

After that. Your non-root user will use substitutes.
source: https://docs.cachix.org/faq#why-is-nix-not-picking-up-on-any-of-the-pre-built-artifacts

5490: <p>I'm preparing the Plutus Pioneer program and installing the environment.</p>
<p>After installing <code>nix</code> and updating the &quot;IOHK binary cache&quot;, I tried to do <code>nix build</code> but it seems that it is building and compiling <code>ghc</code> as shown below and it takes a very long time.</p>
<pre><code>MyMac$ nix build -f default.nix plutus.haskell.packages.plutus-core
trace: To materialize project.plan-nix for Agda entirely, pass a writable path as the `materialized` argument and run the 'updateMaterialized' script in 'passthru'.
[1/1/619 built] building ghc-8.6.5 (buildPhase): clang-7: warning: argument unu
</code></pre>
<p>Current <strong>nix.conf</strong></p>
<pre><code>substituters        = https://hydra.iohk.io https://iohk.cachix.org https://cache.nixos.org/
trusted-public-keys = hydra.iohk.io:f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ= iohk.cachix.org-1:DpRUyj7h7V830dp/i6Nti+NEO2/nhblbov/8MW7Rqoo= cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=

sandbox = true
extra-sandbox-paths = /System/Library/Frameworks /System/Library/PrivateFrameworks /usr/lib /private/tmp /private/var/tmp /usr/bin/env
extra-experimental-features = nix-command
build-users-group = nixbld
</code></pre>
<p>I found the following warning message:</p>
<blockquote>
<p>If you want to use Nix with this project, make sure to set up the IOHK
binary cache. If you do not do this, you will end up building GHC,
which takes several hours. If you find yourself building GHC, STOP and
fix the cache.</p>
</blockquote>
<p>Could you guide me how I can fix the cache?</p>
<p>Thanks in advance.</p>
 6092: <p>It may be the case that you edited your nix.conf file after you launched nix-daemon.
You would need to kill and start the daemon again to pick up the updated nix.conf:</p>
<blockquote>
<p>$ sudo pkill nix-daemon</p>
</blockquote>
<p>and then</p>
<blockquote>
<p>$ sudo nix-daemon &amp;</p>
</blockquote>
<p>After that. Your non-root user will use substitutes.</p>
<p>source: <a href="https://docs.cachix.org/faq#why-is-nix-not-picking-up-on-any-of-the-pre-built-artifacts" rel="nofollow noreferrer">https://docs.cachix.org/faq#why-is-nix-not-picking-up-on-any-of-the-pre-built-artifacts</a></p>
