+: **EDITOR**
+If not already set, sets the default editor. Falls back to vi(1),
+if vim(1) is not available.
+
+: **MAIL**
+The mailbox file for the current user is set to /var/mail/$USER, if not
+already set otherwise.
+
+: **PAGER**
+Set less(1) as default pager, if not already set to something different.
+