diff --git a/data/apps/helpers.d/utils b/data/apps/helpers.d/utils
index a6755e3c8..165a394d3 100644
--- a/data/apps/helpers.d/utils
+++ b/data/apps/helpers.d/utils
@@ -1,5 +1,7 @@
 # Extract a key from a plain command output
 #
+# example: yunohost user info tata --output-as plain | ynh_get_plain_key mail
+#
 # usage: ynh_get_plain_key key [subkey [subsubkey ...]]
 # | ret: string - the key's value
 ynh_get_plain_key() {