diff --git a/doc/erko_howto_tools.txt b/doc/erko_howto_tools.txt
index ffcba3c8a1f0731cfd5f24086d9772c553675e68..8836bb00823648edcb49f1f7997680deb386fd3c 100755
--- a/doc/erko_howto_tools.txt
+++ b/doc/erko_howto_tools.txt
@@ -1408,3 +1408,6 @@ python3 -m pip install flake8
 
 # add to path in ~/.bashrc
 export PATH=~/.local/bin:$PATH
+
+# run flake8 in dir, to check all py files in that dir and below
+> flake8