diff --git a/update.sh b/update.sh
index 5b64d65c8e..d26ada624a 100755
--- a/update.sh
+++ b/update.sh
@@ -18,9 +18,8 @@ for version in "${versions[@]}"; do
 	fullVersion="$(grep -m1 -A10 "^Package: postgresql-$version\$" "$packages" | grep -m1 '^Version: ' | cut -d' ' -f2)"
 	(
 		set -x
-		cp docker-entrypoint.sh Dockerfile.template "$version/"
-		mv "$version/Dockerfile.template" "$version/Dockerfile"
-		sed -i 's/%%PG_MAJOR%%/'$version'/g; s/%%PG_VERSION%%/'$fullVersion'/g' "$version/Dockerfile"
+		cp docker-entrypoint.sh "$version/"
+		sed 's/%%PG_MAJOR%%/'$version'/g; s/%%PG_VERSION%%/'$fullVersion'/g' Dockerfile.template > "$version/Dockerfile"
 	)
 	
 	travisEnv='\n  - VERSION='"$version$travisEnv"