diff --git a/src/nix-build/nix-build.cc b/src/nix-build/nix-build.cc
index 2b36846cd..3e1081c05 100755
--- a/src/nix-build/nix-build.cc
+++ b/src/nix-build/nix-build.cc
@@ -412,7 +412,7 @@ static void _main(int argc, char * * argv)
         auto rcfile = (Path) tmpDir + "/rc";
         writeFile(rcfile, fmt(
                 (keepTmp ? "" : "rm -rf '%1%'; "s) +
-                "[ -n \"$PS1\" ] && [ -e ~/.bashrc ] && source ~/.bashrc; "
+                (pure ? "" : "[ -n \"$PS1\" ] && [ -e ~/.bashrc ] && source ~/.bashrc;")
                 "%2%"
                 "dontAddDisableDepTrack=1; "
                 "[ -e $stdenv/setup ] && source $stdenv/setup; "