You can generate script of GUI functionality by clicking below high-lighted option in the image.

It will give you all the below options.

You can use below script to rename SA account. Script will work with SQL Server 2005 and higer versions.

 ALTER LOGIN sa Disable;
ALTER LOGIN sa WITH NAME = [Jugal];


Check my new article on MSSQLTips

http://www.mssqltips.com/tip.asp?tip=2175

To limit the size of the SQL Server error log, the sp_cycle_errorlog system stored procedure can be issued to start a new error log. 

To recycle SQL Server Agent log you can execute sp_cycle_agent_errorlog system stored procedure.

http://www.mssqltips.com/tip.asp?tip=2164