diff --git a/nix/install b/nix/install
index 342aa0daf1..023a5ac202 100644
--- a/nix/install
+++ b/nix/install
@@ -4,16 +4,16 @@
 # downloading a binary distribution and running its installer script
 # (which in turn creates and populates /nix).
 
-tarball=nix-binary-tarball.tar.bz2
 unpack=nix-binary-tarball-unpack
 
-cleanup() {
-    rm -rf "$unpack" "$tarball"
+require_util() {
+    type "$1" > /dev/null 2>&1 || which "$1" > /dev/null 2>&1 ||
+        oops "you do not have \`$1' installed, which i need to $2"
 }
 
 oops() {
     echo "$0: $@" >&2
-    cleanup
+    rm -rf "$unpack"
     exit 1
 }
 
@@ -26,19 +26,16 @@ esac
 
 url="https://nixos.org/releases/nix/nix-1.7/nix-1.7-$system.tar.bz2"
 
-type curl > /dev/null 2>&1 || which curl > /dev/null 2>&1 ||
-    oops "you do not have \`curl' installed," \
-         "which I need to download the binary tarball"
+require_util curl "download the binary tarball"
+require_util bzcat "decompress the binary tarball"
+require_util tar "unpack the binary tarball"
 
-echo "downloading Nix binary tarball for $system from \`$url'..."
-curl -L -o "$tarball" "$url" || oops "failed to download \`$url'"
-
-echo "unpacking binary tarball..."
-mkdir "$unpack"
-tar xf "$tarball" -C "$unpack"
+echo "unpacking Nix binary tarball for $system from \`$url'..."
+mkdir "$unpack" || oops "failed to create \`$unpack' directory"
+curl -L "$url" | bzcat | tar x -C "$unpack" || oops "failed to unpack \`$url'"
 
 [ -e "$unpack"/*/install ] ||
     oops "installation script is missing from the binary tarball!"
 
 "$unpack"/*/install
-cleanup
+rm -rf "$unpack"