diff --git a/krebs/4lib/shell.nix b/krebs/4lib/shell.nix
index 48b220f87..2a6da5c16 100644
--- a/krebs/4lib/shell.nix
+++ b/krebs/4lib/shell.nix
@@ -12,4 +12,11 @@ rec {
       if isSafeChar c then c
       else if c == "\n" then "'\n'"
       else "\\${c}");
+
+  #
+  # shell script generators
+  #
+
+  # example: "${cat (toJSON { foo = "bar"; })} | jq -r .foo"
+  cat = s: "printf '%s' ${escape s}";
 }