diff --git a/todo.sh b/todo.sh
index a21356e..36ef038 100755
--- a/todo.sh
+++ b/todo.sh
@@ -474,6 +474,7 @@ TODOTXT_AUTO_ARCHIVE=${TODOTXT_AUTO_ARCHIVE:-1}
 TODOTXT_DATE_ON_ADD=${TODOTXT_DATE_ON_ADD:-0}
 TODOTXT_DEFAULT_ACTION=${TODOTXT_DEFAULT_ACTION:-}
 TODOTXT_SORT_COMMAND=${TODOTXT_SORT_COMMAND:-env LC_COLLATE=C sort -f -k2}
+TODOTXT_DISABLE_FILTER=${TODOTXT_DISABLE_FILTER:-}
 TODOTXT_FINAL_FILTER=${TODOTXT_FINAL_FILTER:-cat}
 
 # Export all TODOTXT_* variables