diff --git a/samples/landlock/sandboxer.c b/samples/landlock/sandboxer.c
index dba143f62bf5..57565dfd74a2 100644
--- a/samples/landlock/sandboxer.c
+++ b/samples/landlock/sandboxer.c
@@ -296,25 +296,26 @@ static bool check_ruleset_scope(const char *const env_var,
 /* clang-format off */
 
 static const char help[] =
-	"usage: "
-	ENV_FS_RO_NAME "=\"...\" "
-	ENV_FS_RW_NAME "=\"...\" "
-	ENV_TCP_BIND_NAME "=\"...\" "
-	ENV_TCP_CONNECT_NAME "=\"...\" "
-	ENV_SCOPED_NAME "=\"...\" %1$s <cmd> [args]...\n"
+	"usage: " ENV_FS_RO_NAME "=\"...\" " ENV_FS_RW_NAME "=\"...\" "
+	"[other environment variables] %1$s <cmd> [args]...\n"
 	"\n"
-	"Execute a command in a restricted environment.\n"
+	"Execute the given command in a restricted environment.\n"
+	"Multi-valued settings (lists of ports, paths, scopes) are colon-delimited.\n"
 	"\n"
-	"Environment variables containing paths and ports each separated by a colon:\n"
-	"* " ENV_FS_RO_NAME ": list of paths allowed to be used in a read-only way.\n"
-	"* " ENV_FS_RW_NAME ": list of paths allowed to be used in a read-write way.\n"
+	"Mandatory settings:\n"
+	"* " ENV_FS_RO_NAME ": paths allowed to be used in a read-only way\n"
+	"* " ENV_FS_RW_NAME ": paths allowed to be used in a read-write way\n"
 	"\n"
-	"Environment variables containing ports are optional and could be skipped.\n"
-	"* " ENV_TCP_BIND_NAME ": list of ports allowed to bind (server).\n"
-	"* " ENV_TCP_CONNECT_NAME ": list of ports allowed to connect (client).\n"
-	"* " ENV_SCOPED_NAME ": list of scoped IPCs.\n"
+	"Optional settings (when not set, their associated access check "
+	"is always allowed, which is different from an empty string which "
+	"means an empty list):\n"
+	"* " ENV_TCP_BIND_NAME ": ports allowed to bind (server)\n"
+	"* " ENV_TCP_CONNECT_NAME ": ports allowed to connect (client)\n"
+	"* " ENV_SCOPED_NAME ": actions denied on the outside of the landlock domain\n"
+	"  - \"a\" to restrict opening abstract unix sockets\n"
+	"  - \"s\" to restrict sending signals\n"
 	"\n"
-	"example:\n"
+	"Example:\n"
 	ENV_FS_RO_NAME "=\"${PATH}:/lib:/usr:/proc:/etc:/dev/urandom\" "
 	ENV_FS_RW_NAME "=\"/dev/null:/dev/full:/dev/zero:/dev/pts:/tmp\" "
 	ENV_TCP_BIND_NAME "=\"9418\" "