How to recover root password in RHEL 6 ?

Boot the system and log in into grub.

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How to Configure DHCP in RHEL 6 ?

Before starting make sure that your system has a Static IP Address.

My ip address is as following.

IP- 192.168.1.65
Subnet- 255.255.255.0

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How to change an Oracle Database password temporarily.

Lets unlock the hr user and give it a password.

SQL> alter user hr identified by hr account unlock;

User altered.

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Undo tablespace recovery in case of no backups.

This method to recover Undo tablespace is not a substitute for recovery procedures
through backups as mentioned in the official Oracle documentation.

But if you get stuck in a situation where you don’t have any backups and need to
recover your Undo tablespace , then use this method as a last resort.

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Drop a Target Database Using RMAN in Oracle 10g.

Beginning with Oracle 10g Release 1 onwards, A database can be dropped
by executing few simple statements.

With this method all datafiles, controlfiles, Redo log files, Spfile, Archived
Redo log files, backups will be dropped along with the target database.

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Oracle 10g Clone database using Rman.

Clone Database on the same machine (locally). 

1) First make sure your database is in archivelog mode.
2) Make a fresh backup of your database using Rman.
3) The SID of the database which I have is “orcl”.
   The cloned database name will be “dup”.
4) Add the following lines to listener.ora file.

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How to set AUTOTRACE in Oracle 10g.

[root@localhost ~]# su - oracle
[oracle@localhost ~]$ export ORACLE_SID=orcl
[oracle@localhost ~]$ sqlplus

username:system
password:password

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