Locking Hints and Examples are as follows. The usage of them is same same but effect is different.
The xp_cmdshell option is a server configuration option that enables system administrators to control whether the xp_cmdshell extended stored procedure can be executed on a system.
SQL SERVER – Query to Find Seed Values, Increment Values and Current Identity Column value of the table
SQL SERVER – Understanding new Index Type of SQL Server 2005 Included Column Index along with Clustered Index and Non-clustered Index
Only 1 allowed per table
Physically rearranges the data in the table to conform to the index constraints
For use on columns that are frequently searched for ranges of data
For use on columns with low selectivity
This is summary blog post for SQL Server Interview Questions and Answers.