diff --git a/modules/darwin/builder.nix b/modules/darwin/builder.nix
index ef1c884..26675f1 100644
--- a/modules/darwin/builder.nix
+++ b/modules/darwin/builder.nix
@@ -15,7 +15,7 @@
       config.nix.package
       pkgs.coreutils
     ];
-    script = import "${inputs.self}/modules/shared/free-space.nix";
+    script = builtins.readFile "${inputs.self}/modules/shared/free-space.bash";
   };
 
   # https://github.com/LnL7/nix-darwin/blob/230a197063de9287128e2c68a7a4b0cd7d0b50a7/modules/nix/default.nix#L201
diff --git a/modules/nixos/builder.nix b/modules/nixos/builder.nix
index ca17e23..d6e1061 100644
--- a/modules/nixos/builder.nix
+++ b/modules/nixos/builder.nix
@@ -14,7 +14,7 @@
       config.nix.package
       pkgs.coreutils
     ];
-    script = import "${inputs.self}/modules/shared/free-space.nix";
+    script = builtins.readFile "${inputs.self}/modules/shared/free-space.bash";
   };
 
   # Bump the open files limit so that non-root users can run NixOS VM tests
diff --git a/modules/shared/free-space.bash b/modules/shared/free-space.bash
new file mode 100644
index 0000000..e436b8f
--- /dev/null
+++ b/modules/shared/free-space.bash
@@ -0,0 +1,10 @@
+# https://git.lix.systems/the-distro/infra/commit/15a684c5d7e1ee25cdd6f2941ed17c01aa107781
+nix-env --delete-generations 1d --profile /nix/var/nix/profiles/system
+while :; do
+  used=$(($(stat -f --format="100-(100*%a/%b)" /)))
+  if [[ $used -gt "85" ]]; then
+    nix-store --gc --max-freed 100G
+  else
+    break
+  fi
+done
diff --git a/modules/shared/free-space.nix b/modules/shared/free-space.nix
deleted file mode 100644
index f8c3242..0000000
--- a/modules/shared/free-space.nix
+++ /dev/null
@@ -1,12 +0,0 @@
-# https://git.lix.systems/the-distro/infra/commit/15a684c5d7e1ee25cdd6f2941ed17c01aa107781
-''
-  nix-env --delete-generations 1d --profile /nix/var/nix/profiles/system
-  while : ; do
-    used=$(($(stat -f --format="100-(100*%a/%b)" /)))
-    if [[ $used -gt "85" ]]; then
-      nix-store --gc --max-freed 100G
-    else
-      break
-    fi
-  done
-''