diff --git a/pbc b/pbc
index 0e29ff8..587efde 100755
--- a/pbc
+++ b/pbc
@@ -277,6 +277,8 @@ if $FULL_HELP; then
   exit $?
 fi
 
+[ -z "$action" ] && usage >&2 && exit 255
+
 if [ "$action" == 'install' ]; then
   if [ -f "$cfgfile" ]; then
     source "$cfgfile" || exit $?