diff --git a/TODO b/TODO
index f9517f4..be71dac 100644
--- a/TODO
+++ b/TODO
@@ -10,6 +10,10 @@
   __HOSTSHORT__  # Leftmost component of hostname as passed to program
   __TIME__       # Time in HHMMSS format
 
+- Added an "execution builtin".  This runs a command of your
+  choosing (on the local machine) and assigns the results to
+  a user-defined variable.
+  
 - Added -E to redirect all stderr output to stdout instead,
 
 - Added -T timeout option (default is 15 sec).
@@ -57,13 +61,11 @@
 ----
 
 
-- Add:  .define foo = ! string
-
-- Recursive .define replacements with loop detection and explain how
-  to use to override bultins.  
-
 - Do testmode substitions.
 
+- Note importance of giving variables distinctive names so they do
+  not accidentally get substituted.
+
 - Make note that all cmdfiles are read in and THEN evaluated at *runtime*:
 
    echo __HOSTNUM__
@@ -77,6 +79,8 @@
   *locally* and are reevaluated for each new host being processed.
   e.g., Timestamp will change with a big list of hosts.
 
+  Include material on execution variables.
+
 - Add note about this being a *NIX, Python 2 only prog.