diff --git a/modules/lib/default.nix b/modules/lib/default.nix
index 5c273f15..8291be0b 100644
--- a/modules/lib/default.nix
+++ b/modules/lib/default.nix
@@ -15,4 +15,6 @@
         entryAfter = d.dagEntryAfter;
         entryBefore = d.dagEntryBefore;
       };
+
+  shell = import ./shell.nix { inherit lib; };
 }
diff --git a/modules/lib/shell.nix b/modules/lib/shell.nix
new file mode 100644
index 00000000..f1443c54
--- /dev/null
+++ b/modules/lib/shell.nix
@@ -0,0 +1,11 @@
+{ lib }:
+
+rec {
+  # Produces a Bourne shell like variable export statement.
+  export = n: v: "export ${n}=\"${toString v}\"";
+
+  # Given an attribute set containing shell variable names and their
+  # assignment, this function produces a string containing an export
+  # statement for each set entry.
+  exportAll = vars: lib.concatStringsSep "\n" (lib.mapAttrsToList export vars);
+}