How to check oracle users, alter user password, unlock user

HOW TO CHECK ORACLE USERS AND THEIR STATUS:
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SQL> SELECT USERNAME,ACCOUNT_STATUS,EXPIRY_DATE from dba_users;

USERNAME ACCOUNT_STATUS EXPIRY_DA
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OUTLN OPEN 15-MAR-14
PEOPLE OPEN 11-JUL-17
PS OPEN 05-JUN-17
SYS OPEN 15-MAR-14
SYSTEM OPEN 05-JUN-17
SYSADM EXPIRED 12-JUN-17
APPQOSSYS EXPIRED & LOCKED 16-SEP-13
DIP EXPIRED & LOCKED 16-SEP-13
DBSNMP EXPIRED & LOCKED 16-SEP-13
ORACLE_OCM EXPIRED & LOCKED 16-SEP-13

10 rows selected.

CHANGE USER PASSWORD:
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ALTER USER myuser IDENTIFIED BY new_password;

ALTER USER myuser ACCOUNT LOCK;
ALTER USER myuser ACCOUNT UNLOCK;
ALTER USER myuser PASSWORD EXPIRE;