How to find Queries Running in the Database(V$SQL) and also how to kill sessions

some times we want to know what are queries that are getting executed when any process is run..one way of finding it is using the V$Sql..the SID and Serial# can be used to kill the session in case of long running queries
set pagesize 24
set newpage 1
set linesize 125
column sql_text format a100
column user_name format a12
select b.sid, b.serial# , 
substr(b.username,1,12) user_name, 
a.sql_text
from v$sql a, v$session b
where a.hash_value = b.sql_hash_value
and sql_text not like '%from v$sql s, v$session u%'
order by b.sid;


SQL> @cur_sql
sid serial user_name sql_text
5 390 apps select f.file#, f.block#, f.ts#, f.length from fet$ f, ts$ t where t.ts#=f.ts# and t.dflextpct!=0 an d t.bitmapped=0

To kill a session use the below command
ALTER SYSTEM KILL SESSION 'SID, SER#';
alter system kill session '5,390';