What does the s means in the user permissions?

[rveri-admin]

Experts, 

Please help understanding the type of file pemissions with s , is it setgid ? ,

-r-sr-x--- 1 cmuser orasys 1057 Jan 5 2013 ccmuser
-r-sr-x--- 1 dmuser orasys 1057 Jan 5 2013 cdmuser

Pleae help to understand :

1. why it is used for.

2. How to set this permission . 

hp-uxv3 .  Thanks. 

[Bill Hassell]

man ls

and 

man chmod

ll shows the current values, chmod can change the values (aka, permissions)

[Dennis Handly]

>file permissions with s, is it setgid?

-r-sr-x--- 1 cmuser orasys ccmuser

No, your "s" is in the user portion.

>1. Why it is used for?

To do setuid scripts.

>2. How to set this permission?

chmod u+s file