diff --git a/todo.sh b/todo.sh
index 7c43c1eb..026739a5 100755
--- a/todo.sh
+++ b/todo.sh
@@ -1346,8 +1346,8 @@ case $action in
 "listpri" | "lsp" )
     shift ## was "listpri", new $1 is priority to list or first TERM
 
-    pri=$(printf "%s\n" "$1" | grep '^\([A-Za-z]\|[A-Za-z]-[A-Za-z]\|[A-Z][A-Z-]*[A-Z]\)$') && shift || pri="A-Z"
-    post_filter_command="${post_filter_command:-}${post_filter_command:+ | }grep '^ *[0-9]\+ ([${pri^^}]) '"
+    pri=$(set -o pipefail; printf "%s\n" "$1" | grep '^\([A-Za-z]\|[A-Za-z]-[A-Za-z]\|[A-Z][A-Z-]*[A-Z]\)$' | tr '[:lower:]' '[:upper:]') && shift || pri="A-Z"
+    post_filter_command="${post_filter_command:-}${post_filter_command:+ | }grep '^ *[0-9]\+ ([${pri}]) '"
     _list "$TODO_FILE" "$@"
     ;;