diff --git a/Formula/msg-cli.rb b/Formula/msg-cli.rb
index ca46041..95c7cb8 100644
--- a/Formula/msg-cli.rb
+++ b/Formula/msg-cli.rb
@@ -37,7 +37,7 @@ class MsgCli < Formula
     ENV["GUILE_LOAD_COMPILED_PATH"] = HOMEBREW_PREFIX/"lib/guile/3.0/site-ccache"
     ENV["GUILE_SYSTEM_EXTENSIONS_PATH"] = HOMEBREW_PREFIX/"lib/guile/3.0/extensions"
     system "autoreconf", "-vif"
-    system "echo", "#{opt_prefix}"
+    system "echo", "#{opt_lib}"
     system "./configure", "--prefix=#{prefix}"
     system "make" 
     system "make", "install"