row keys through the hbase shell?

I am using

 scan 'table_name', { COLUMNS => 'column_family:column_qualifier', LIMIT => 2 }

to list 2 rows in a hbase table but I would like to know if it is possible to achieve following using hbase shell:

Questions

1. list all row keys through the hbase shell?
2. list only those rows, whose row keys have a particular word in it?