If any command is not working in hbase please follow below steps to restart Hbase shell


1)  cd /usr/lib/hbase-0.96.2-hadoop2/

2)  sudo rm -r hbasestorage/*

3)  sudo rm -r logs/*

4) ./bin/start-hbase.sh

5)  hbase shell


you can also execute below command to alter table schema


1. Creating table MyTable with column family cf1


create 'MyTable', 'cf'


2. Adding recoreds in MyTable


put 'MyTable','row1','cf:name','abhishek'

put 'MyTable','row1','cf:name','andy'

put 'MyTable','row2','cf:name','Ajay'


3. Disable table to make changes in table schema


disable 'MyTable'


4. Alter table, here we are adding one more column family naming cf2


alter 'MyTable', {NAME => 'cf2'}


5. Enable table


enable 'MyTable'


6.  Adding recoreds in column family cf2 in MyTable 


put 'MyTable','row3','cf2:name','Ajay'

 

7. Now do scan in MyTable and you can see the changes

 

scan 'MyTable'


Now by executing above steps will change my table, you can refer below screen shot for your reference