diff --git a/doc/erko_howto_tools.txt b/doc/erko_howto_tools.txt
index 97487abd2dadbbebb9c1daec1b3f5e622a60c561..30a435bed2fb4d056ff11746a2e36191807bcd2d 100755
--- a/doc/erko_howto_tools.txt
+++ b/doc/erko_howto_tools.txt
@@ -1353,6 +1353,9 @@ sudo apt-get upgrade
 sudo apt-get dist-upgrade
 sudo apt remove
 
+# filesystem root
+df -h  # free up space with sudo apt autoremove --> may 2024 agian 21G free of 57G in / (was 1G)
+
 # Login on dop386 and then power off:
 > sudo shutdown