Install TFTP Server in Ubuntu 14.04

1. Install the package.

$ sudo apt-get install tftpd-hpa

2. Edit config file as follows.

$ sudo vi /etc/default/tftpd-hpa

# /etc/default/tftpd-hpa
TFTP_USERNAME="tftp"
TFTP_DIRECTORY="/tftpboot"
TFTP_ADDRESS="0.0.0.0:69"
TFTP_OPTIONS="-s -c -l"

Note: -l for listening all time this avoided the timeout issue, -c to create files in tftfp folder.

3. Create TFTP folder.

sudo mkdir /tftpboot

$ sudo chmod -R 777 /tftpboot

$ sudo chown -R nobody /tftpboot

4. Finally restart the app to apply new configuration. 

sudo service tftpd-hpa restart

See whats there in root partition

When we check root partition for whats eating up the space, we will get all other partitions details,

 to avoid this..

du -sh --exclude=tmp --exclude=var --exclude=usr --exclude=home --exclude=boot --exclude=proc *

this will exclude the tmp, var, usr, home, boot, proc from root partition...  

Delete files older than certain days in linux

Here following command will delete files older than 31 days in current folder.

find -ctime +31 -delete

Check Serial port of Linux

dmesg | grep tty

Emptying contents of a log or text file

$ > alert_UAT.log

This command will empty alert_UAT.log file.

Installing Oracle 11r2 in RHEL / CentOS (simple installation procedure with OL yum repository for learning purpose)

1. Install RHEL or CentOS . (on completion of installation dont forget to disable Firewall & SE linux)

2. Complete the prerequisites for 11G installation with Public OL yum repository as per following link.
http://www.oracle.com/technetwork/articles/servers-storage-admin/ginnydbinstallonlinux-488779.html

3. Edit /etc/hosts and add a fully qualified name for server like follows.


<IP-address>  <fully-qualified-machine-name>  <machine-name>
192.168.1.10 oratest.mydomain.com oratest


4. Set environment variable for bash shell like follows.

ORACLE_BASE=/oratest/app/oracle; export ORACLE_BASE
ORACLE_HOME=$ORACLE_BASE/product/11.2.0/dbhome_1; export ORACLE_HOME
ORACLE_SID=DBtest; export ORACLE_SID

PATH=/usr/sbin:$PATH; export PATH
PATH=$ORACLE_HOME/bin:$PATH; export PATH

LD_LIBRARY_PATH=$ORACLE_HOME/lib:/lib:/usr/lib; export LD_LIBRARY_PATH
CLASSPATH=$ORACLE_HOME/jlib:$ORACLE_HOME/rdbms/jlib; export CLASSPATH

5. Set the DISPLAY environment. DISPLAY=<machine-name>:0.0; export DISPLAY

6. Download RDBMS software from following link

http://www.oracle.com/technetwork/database/enterprise-edition/downloads/index.html

7. Once download complete unzip the files by unzip<filename>.zip

8. Goto OraDB11g/database (Extracted folder)

9. Make Directory for oracle software installation and give permission for same.
mkdir -p /disk1/DB
cd /disk1
chown -R oracle:oinstall /DB

10. Run the installer ./runInstaller

This will start the installation.

Install Shrewsoft VPN client in Ubuntu for Juniper Firewall

1. Download ike-2.2.0-rc-2.tgz or Latest Version from http://www.shrew.net/download.

2. Unzip the Downloaded file by following command $tar -xzvf shrewsoft-client.tgz

3. Go through the Readme file in extracted folder.

4. Install the prerequisites for Shrewsoft VPN client. like following.

sudo apt-get install gcc flex bison cmake openssl libssl-dev qt4-dev-tools libedit-dev build-essential

5. Go to the extracted folder IKE

6. Run following commands one by one.

$cmake -DCMAKE_INSTALL_PREFIX=/usr/local-DQTGUI=YES -DETCDIR=/etc -DNATT=YES
$cmake
$make
$sudo make install

$sudo cp ~/Downloads/ike/source/iked/iked.conf.sample /usr/local/etc/iked.conf

7. Use a text editor to edit (as root) /etc/sysctl.conf
8. Change the following Entries from 1 to 0 (if these values are not defined you will need to add
them in order to override the default setting of 1).
net.ipv4.conf.default.rp _ filter=0
net.ipv4.conf.all.rp _ filter=0
9. Use a text editor to edit (as root) /etc/sysctl.d/10-network-security.conf
10. Change the following Entries from 1 to 0 (if these values are not defined you will need to add
them in order to override the default setting of 1).
net.ipv4.conf.default.rp _ filter=0
net.ipv4.conf.all.rp _ filter=0
11. Reboot the PC.
12. Execute the following command to confirm settings change has taken affect:
$> sysctl -a | egrep rp_filter | egrep -v arp
net.ipv4.conf.all.rp _ filter = 0
net.ipv4.conf.default.rp _ filter = 0
net.ipv4.conf.lo.rp _ filter = 0
net.ipv4.conf.eth0.rp _ filter = 0

13. start IKED
$sudo iked

14. Start GUI and configure the VPN or Import Porifile.
$qikea

15. If GUI not starting install it. $ sudo apt-get install ike-qtgui

VNC Server in RHEL, CentOS 5 & 6

1.Install VNC Server (EL:5 Servers)

#yum install vnc-server

2.create VNC login password

#vncpasswd

3.Edit following file and uncomment the two lines as mentioned in file.

#vi .vnc/xstartup

4.start an instance of VNC server & Check the log for moredetails.

#vncserver

5. Start VNC client in hostname field type ipaddress and :1 (xxx.xxx.xxx.xxx:1) and for authentication use the password set in Step two.

1.Install VNC Server (EL:6 Servers)

#yum install tigervnc-server

2.create VNC login password

#vncpasswd

3.Edit following file and  add two lines like following.

#vi /etc/sysconfig/vncservers

VNCSERVERS="1:root"
VNCSERVERARGS[1]="-geometry 1024x768"

4.start an instance of VNC server & Check the log for moredetails.

#service vncserver start

5. Start VNC client in hostname field type ipaddress and :1 (xxx.xxx.xxx.xxx:1) and for authentication use the password set in Step two.


Install VNC in CentOS-7

https://www.digitalocean.com/community/tutorials/how-to-install-and-configure-vnc-remote-access-for-the-gnome-desktop-on-centos-7

Run Oracle E-Business suite / forms in ubuntu firefox

There are two options One is through PPA and another Manual.

Option-1 (PPA)

sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update
sudo apt-get install oracle-java7-installer (for Java-7)
sudo apt-get install oracle-java8-installer (for Java-8)

Option-2 (Manual)

Step1: Download java from http://www.java.com/en/ as per you operating system (32 / 64 Bit)


Step 2 Install Oracle JAVA (Here i used Version 7 Update 55 64Bit)

Open Terminal go to the in which we downloaded JAVA (Mostly Downloads)

 Unzip the tar file

$ tar -xvf jre-7u55-linux-x64.tar.gz

$ sudo mv jre1.7.0_55 /usr/lib/jvm/

$ sudo update-alternatives --install "/usr/bin/java" "java" "/usr/lib/jvm/jre1.7.0_55/bin/java" 1

$ sudo update-alternatives --install "/usr/lib/mozilla/plugins/libjavaplugin.so" "mozilla-javaplugin.so" "/usr/lib/jvm/jre1.7.0_55/lib/amd64/libnpjp2.so" 1


IMPORTANT choose the java you installed as default (SUN / Oracle JAVA)

 $ sudo update-alternatives --config java
 $ sudo update-alternatives --config mozilla-javaplugin.so

There is a security issue for self signed certificates, to get rid of this issue.

open control panel by executing following command

$ /usr/lib/jvm/jre1.7.0_55/bin/ControlPanel

Add site name with port number like follows.

http://vision.testing.com:8000


Restart Firefox now oracle forms will start working.

Check size of a current folder in Linux

du -sk .