diff --git a/pkgs/stdenv/generic/builder.sh b/pkgs/stdenv/generic/builder.sh
index 98b90144611a..fd4c17ca2519 100644
--- a/pkgs/stdenv/generic/builder.sh
+++ b/pkgs/stdenv/generic/builder.sh
@@ -9,10 +9,11 @@ mkdir $out
 echo "$preHook" > $out/setup
 cat "$setup" >> $out/setup
 
-sed -i "$out/setup" \
-    -e "s^@initialPath@^$initialPath^g" \
+sed -e "s^@initialPath@^$initialPath^g" \
     -e "s^@gcc@^$gcc^g" \
-    -e "s^@shell@^$shell^g"
+    -e "s^@shell@^$shell^g" \
+    < $out/setup > $out/setup.tmp
+mv $out/setup.tmp $out/setup
 
 # Allow the user to install stdenv using nix-env and get the packages
 # in stdenv.