diff --git a/src/nix-build/nix-build.cc b/src/nix-build/nix-build.cc
index e302aca67..b6b31b46e 100644
--- a/src/nix-build/nix-build.cc
+++ b/src/nix-build/nix-build.cc
@@ -644,7 +644,7 @@ static void main_nix_build(int argc, char * * argv)
                 escapeShellArgAlways(*shell),
                 (getenv("TZ") ? (std::string("export TZ=") + escapeShellArgAlways(getenv("TZ")) + "; ") : ""),
                 envCommand);
-        vomit("Sourcing nix-shell with file %s and contents:\n%s", rcfile, rc);
+        debug("Sourcing nix-shell with file %s and contents:\n%s", rcfile, rc);
         writeFile(rcfile, rc);
 
         Strings envStrs;