The Whois servers provide results in ASCII.
These can be queried using any number of free whois clients, and use specific whois query commands.
Query Controls
Whois query controls fall into two categories: those that specify the type of field and those that modify the interpretation of the input or determine the type of output to provide.
Object Type Control The following keywords restrict a search to a specific object type:
| DOmain | Search only domain objects. The input string is searched in the Name field. |
| HOst | Search only name server objects. The input string is searched in the Name field and the IP Address field. |
| Contact | Search only contact objects. The input string is searched in the ID field. |
| Registrar | Search only registrar objects. The input string is searched in the Name field. |
By default, if no object type control is specified, then the Name field of the Domain object is searched.
Additional reading[]
http://www.icann.org/tlds/agreements/info/appendix-05-08dec06.htm