How to determine Oracle Database And OS version

The following query determine you the database version

SQL> select * from v$version;

BANNER
----------------------------------------------------------------
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Prod
PL/SQL Release 10.2.0.1.0 - Production
CORE    10.2.0.1.0      Production
TNS for 32-bit Windows: Version 10.2.0.1.0 - Production
NLSRTL Version 10.2.0.1.0 – Production

Alternatively, you can query from product_component_version.

UNIX Crontab Basics

A crontab file has five fields for specifying day , date and time followed  by the command to be run at that interval.

#——————————————————————————————

# Minute     Hour    Month Day      Month       Weekday                      Command

#  0-59       0-23      1-31                 1-12           0-6 (0=Sunday)

#——————————————————————————————

OS commands Very useful for DBAs and OS files management

Finding OS Version and Bit

OS Version

uname -a

AIX <ServerName> 3 5 00C8E96B4C00

uname

AIX

oslevel -r

5300-06

Some useful Linux Command for DBA

ls: List files
cp: Copy files
mv: Move and rename files
mkdir: Make a directory
alias: Define command macros
rm: Remove files and directories
more: Page through output
head: Show beginning of file contents
tail: Show end of file contents

How to take file backup from Linux Server

This article describes a simple backup method that I use every day to backup my home Linux systems. It’s an easy method that non-technical Linux users can use to backup their important data. We’ll discuss the decisions you have to make in order to do a thorough backup.

Changing Hostname on RHEL

It is possible to change the hostname without reboot; this is very helpful in Production environment.

Here I have change the hostname of the server without restarting on RHEL

Step 01: Change the HOSTNAME line in /etc/sysconfig/network

[root@aca800de root]# vi /etc/sysconfig/network
HOSTNAME=vasappserver1

Step 02: Change the hostname (FQDN and alias) in /etc/hosts

[root@aca800de root]# vi /etc/hosts
# Do not remove the following line, or various programs
# that require network functionality will fail.
127.0.0.1         localhost.localdomain         localhost
172.168.0.222     vasappserver1.ring.com.bd     vasappserver1

Step 03: Run /bin/hostname new_hostname for the hostname change to take effect immediately.

[root@aca800de root]# /bin/hostname vasappserver1
[root@aca800de root]# hostname
vasappserver1

Step 04: Run /sbin/service syslog restart for syslog to log using the new hostname.

[root@aca800de root]# service syslog restart
Shutting down kernel logger:                               [  OK  ]
Shutting down system logger:                               [  OK  ]
Starting system logger:                                    [  OK  ]
Starting kernel logger:                                    [  OK  ]