diff --git a/usr.sbin/bsdconfig/share/strings.subr b/usr.sbin/bsdconfig/share/strings.subr
index bf0604aa8142..f9e33c75d835 100644
--- a/usr.sbin/bsdconfig/share/strings.subr
+++ b/usr.sbin/bsdconfig/share/strings.subr
@@ -146,7 +146,11 @@ f_substr()
 		fi
 	done
 
-	setvar "$__var_to_set" "$__tmp"
+	if [ "$__var_to_set" ]; then
+		setvar "$__var_to_set" "$__tmp"
+	else
+		echo "$__tmp"
+	fi
 }
 
 # f_sprintf $var_to_set $format [$arguments ...]