Merge pull request #8820 from anlancs/master-vtysh-hostname

doc: add a note of hostname/domainname for vtysh

diff --cc doc/user/basic.rst
index 0db23612966a99a4868bfc8bea45eb6fba092d35,3e85a08179ab2388426a9829b6b939b9e95a4276..452794e3a895050bf5b4ec586a08ac0b7cdbb3a2
--- 1/doc/user/basic.rst
--- 2/doc/user/basic.rst
+++ b/doc/user/basic.rst
@@@ -58,12 -58,14 +58,18 @@@ Basic Config Command
  
  .. clicmd:: hostname HOSTNAME
  
-    Set hostname of the router.
+    Set hostname of the router. It is only for current ``vtysh``, it will not be
+    saved to any configuration file even with ``write file``.
+ 
+ .. clicmd:: domainname DOMAINNAME
+ 
+    Set domainname of the router. It is only for current ``vtysh``, it will not
+    be saved to any configuration file even with ``write file``.
  
 +.. clicmd:: domainname DOMAINNAME
 +
 +   Set domainname of the router.
 +
  .. clicmd:: password PASSWORD
  
     Set password for vty interface. The ``no`` form of the command deletes the