Document bash files in system/

Signed-off-by: Severin Kaderli <severin.kaderli@gmail.com>

system/.bash_logout

@@ -1,8 +1,18 @@
 #!/bin/bash
-# ~/.bash_logout: executed by bash(1) when login shell exits.
-
-# when leaving the console clear the screen to increase privacy
+# 
+# SCRIPT NAME:
+# .bash_logout
+#
+# AUTHOR:
+# Severin Kaderli <severin.kaderli@gmail.com>
+#
+# DESCRIPTION:
+# This script is executed when the login shell exits.
+#
+# USAGE:
+# This script is automatically executed when the login shell exits.
 
+# Clear console output
 if [ "$SHLVL" = 1 ]; then
     [ -x /usr/bin/clear_console ] && /usr/bin/clear_console -q
 fi