Hbase column families

[Dalia Sobhy]

Hiii all,
I want to make a simple example using hbase. First I made a table called 
"Student" with one column family "info"..
After creating the table, I discovered that I need to add a new column family 
called "courses"..So any idea how to do that using hbase shell.
I tried these commands
>>disable 'student'>> alter 'student', NAME => 'course', VERSIONS => 10
But an error occurred ...
So any help ??