How to Check Shared Memory Usage in Oracle

DBA scripts to check the Free Memory of all SGA pools:

SQL> SELECT * FROM v$sgastat WHERE name = 'free memory';
Press Return to Continue
 POOL        |NAME                               |     BYTES|    CON_ID
------------|-----------------------------------|----------|----------
shared pool |free memory                        |2269549760|         0
large pool  |free memory                        |4080599024|         0
java pool   |free memory                        |1073741824|         0
SQL>

And to check the Free memory of shared pool:

SQL> select pool,name,bytes from v$sgastat where name='free memory' and pool='shared pool';
Press Return to Continue
 POOL        |NAME                               |     BYTES
------------|-----------------------------------|----------
shared pool |free memory                        |2271877880
SQL>