is there a tool or command line that able to add single contact to a user contact list in lync 2010

like 

command.exe /user sip:user1@mydomain.com /contact: sip:external@externaldomain.com

this command or tool able to add the contact without deleting the contact list contacts

I found this for OCS 
http://blogs.technet.com/b/nexthop/archive/2010/11/15/r2manageusercontactlists.aspx

but I can't find something for Lync 2010

There's no command line as such, but take a look here and see if this can do what you need. 

http://www.expta.com/2011/01/introducing-lyncaddcontacts.html

Yeah, LCSCMD is pretty much dead.  There's no great replacement here for this that's not a for-pay tool. 

For Lync 2010, you'll want to use DBIMPEXP and modify the XML (be very very careful with this)

http://www.shudnow.net/2012/10/09/dbimpexp-exe-functionality-integrated-into-lync-2013-preview-management-shell/

For Lync 2013, you'll be using Export-CSUserData and Import-CSUserData.

The popular for pay tool is from Vytru.

http://www.vytru.com/contacts-manager/?gclid=CMGdlIeouL4CFQJeOgodjUYApQ

Edit: I forgot lyncaddcontacts, I've been in the 2013 world too long. That's why you're an MVP

actually this is a good tool but I need to add a lot of contacts to a big number of users but the problem is that it's big number of specific contacts like in this tool

it's something like :

users        contact

user@domain.com contact1@domain2.com

user4@domain.com contact8@domain2.com

user9@domain.com contact32@domain2.com

so it will be hard to do it with this tool

As far as I know, there is no such command line for Lync 2010 and Lync 2013 to add specific contact to the contact list of Lync user.

If you integrate Exchange Server and Lync Server. You can consider to create Distribution Group.

You can add the new contact as a member of the Distribution Group. If you add the Distribution Group previously, the new contact will be updated automatically.