How to install tor in ubuntu


How to install tor in ubuntu:

What is Tor?

Tor is free software and an open network that helps you defend against traffic analysis, a form of network surveillance that threatens personal freedom and privacy, confidential business activities and relationships, and state security.

Why Anonymity Matters?

Tor protects you by bouncing your communications around a distributed network of relays run by volunteers all around the world: it prevents somebody watching your Internet connection from learning what sites you visit, and it prevents the sites you visit from learning your physical location.

For more information visit torproject.

How to setup tor:

$tar xf tor-browser-linux64-4.0.4_en-US.tar.xz


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Setup zabbix on ubuntu

Setup zabbix on ubuntu:

Zabbix is the ultimate open source enterprise-level software designed for monitoring availability and performance of IT infrastructure components.
For more details visit following links,

Install Zabbix:

# wget
# sudo dpkg -i zabbix-release_2.2-1+precise_all.deb
# sudo apt-get update

Install Zabbix Component :

Zabbix server – a central process of Zabbix software that performs monitoring, interacts with Zabbix proxies and agents, calculates triggers, sends notifications; a central repository of data
# sudo apt-get install zabbix-server-mysql

Web frontend – the web interface provided with Zabbix
# sudo apt-get install zabbix-frontend-php

Zabbix agent – a process deployed on monitoring targets to actively monitor local resources and applications
# sudo apt-get install zabbix-agent

Zabbix proxy – a process that may collect data on behalf of Zabbix server, taking some processing load off of the server

Zabbix API – Zabbix API allows you to use the JSON RPC protocol to create, update and fetch Zabbix objects (like hosts, items, graphs and others) or perform any other custom tasks

Zabbix Setup :

PHP configuration for Zabbix frontend:

Apache configuration file for Zabbix frontend is located in /etc/apache2/conf.d/zabbix. Some PHP settings are already configured.

php_value max_execution_time 300
php_value memory_limit 128M
php_value post_max_size 16M
php_value upload_max_filesize 2M
php_value max_input_time 300
# php_value date.timezone Asia/Kolkata

It’s necessary to uncomment the “date.timezone” setting and set the correct timezone for you. After changing the configuration file restart the apache web server.
sudo vim /etc/php5/apache2/php.ini
date.timezone = Asia/Kolkata
#sudo service apache2 restart

Follow installation steps here, http://localhost/zabbix/setup.php#

Zabbix configuration :

Appliance Zabbix setup has the following passwords and other configuration changes:

1: Passwords
Zabbix frontend:

If you change frontend password, do not forget to update password setting web monitoring (Configuration → Hosts, Web for host “Zabbix server”).

To change the database user password it has to be changed in the following locations:

2: File locations

Configuration files are placed in /etc.
Zabbix logfiles are placed in /var/log/zabbix.
Zabbix frontend is placed in /usr/share/zabbix.
Home directory for user zabbix is /etc/zabbix.

3: Changes to Zabbix configuration

Server name for Zabbix frontend set to “Zabbix 2.2 Appliance”;
Frontend timezone is set to Europe/Riga, Zabbix home (this can be modified in /etc/php5/apache2/php.ini);
Disabled triggers and web scenarios are shown by default to reduce confusion.

Thanks you.

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Setup vagrant on ubuntu

Setup vagrant on ubuntu:

Vagrant provides easy to configure, reproducible, and portable work environments built on top of industry-standard technology and controlled by a single consistent workflow to help maximize the productivity and flexibility of you and your team.
To achieve its magic, Vagrant stands on the shoulders of giants. Machines are provisioned on top of VirtualBox, VMware, AWS, or any other provider. Then, industry-standard provisioning tools such as shell scripts, Chef, or Puppet, can be used to automatically install and configure software on the machine.

More details can be found at vagrantup


1) Install dependency :
VirtualBox is a general-purpose full virtualizer for x86 hardware, targeted at server, desktop and embedded use. (VirtualBox)

Add one of the following lines according to your distribution to your /etc/apt/sources.list:
deb precise contrib

#wget -q -O- | sudo apt-key add -
#sudo apt-get install virtualbox-4.3

2) Download and install vagrantup.

#sudo dpkg -i /home/hemant/Downloads/vagrant_1.6.5_x86_64.deb

3) Setup vagrant.
Create a root directory for your project and navigate in it:

#mkdir myproject
#cd myproject

Next, run the initialization command:

a) Pass box as parameter:
#vagrant init [box-name] [box-url]
If a first argument is given, it will prepopulate the setting in the created Vagrantfile. [ex. hashicorp/precise64]
If a second argument is given, it will prepopulate the config.vm.box_url setting in the created Vagrantfile. [ex.]
b) Create a Vagrantfile and update default configuraion.

#vagrant init
#vim Vagrantfile

Modify file, = “precise64″

More Vagrantfile oprions,

#Install dependencies using provision,
config.vm.provision :shell, :path => ""
#Create a private network, which allows host-only access to the machine using a specific IP. :private_network, ip: ""
#Share an additional folder to the guest VM.
config.vm.synced_folder "/h_data", "/v_data", owner: "root", group: "root", :mount_options => ['dmode=777,fmode=777']

This will tell it to use this new box. More boxes can be discover here Vagrantcloud.
Save the file and exit. Now you can deploy the guest machine with the following command:

#vagrant up

This will bring up a VPS running Ubuntu 12.04 LTS 64Bit. To make use of it, you can easily SSH into it:

#vagrant ssh

Vagrant will share the project root folder from the host machine (the one containing the Vagrantfile) with a folder on the guest machine, /vagrant.

You can exit and go back to the host with the following command:


To stop and remove the guest machine and all traces of it,

#vagrant destroy

Use reload command is usually required for changes made in the Vagrantfile to take effect. After making any modifications to the Vagrantfile

#vagrant reload

The configured provisioners will not run again, by default. You can force the provisioners to re-run by specifying the –provision flag.

To add more boxes for other projects use following command adds ‘hashicorp/precise64′ box to Vagrant.

#vagrant box add hashicorp/precise64

Thanks you.

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Ubuntu fix Shellshock bug

Ubuntu fix Shellshock Bug :

Test if your system is vulnerable,

$ env X="() { :;}; echo shellshock" `which bash` -c "echo completed"

If you got “shellshock” in output then it is vulnerable.

Bash has functions, though in a somewhat limited implementation, and it is possible to put these Bash functions into environment variables. This flaw is triggered when extra code is added to the end of these function definitions (inside the enivronment variable).

Download package as per your OS version from fix
For 12.04 64bit LTS,

#dpkg -i /home/hemant/Downloads/bash_4.2-2ubuntu2.2_amd64.deb

The patch used to fix this flaw, ensures that no code is allowed after the end of a Bash function.
So if you run the above example with the patched version of Bash, you should get an output similar to:

$ env X="() { :;}; echo shellshock" `which bash` -c "echo completed"
/bin/bash: warning: X: ignoring function definition attempt
/bin/bash: error importing function definition for `X'

Now, you are safe from Shockshell bug.

For details can be found at,



Thank you.

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PHP multiprocessing using fork

PHP multiprocessing using fork:

Process Control support in PHP implements the Unix style of process creation, program execution, signal handling and process termination.

Find more details at PHP fork

The pcntl_fork() function creates a child process that differs from the parent process only in its PID and PPID.
On success, the PID of the child process is returned in the parent’s thread of execution, and a 0 is returned in the child’s thread of execution.
On failure, a -1 will be returned in the parent’s context, no child process will be created, and a PHP error is raised.
The pcntl_wait($status) function protect against zombie children.

PHP fork is useful when we want process multiple task parallely.

Let’s assume we have following task to perform.
1) updateCache : Time 3s.
1) sentEmail : Time 2s.
1) logEntry : Time 1s.
1) addDBEntry : Time 5s.

If we perform above task in serially the it will take 10 sec(5+3+2+1).
But, if we use parallel processing then it will reduce to 5 sec(largest time among them) using wait to protect against zombie children without returning immediately.

You can also return parent process and make child processes run in background as zombie.

$time_start = microtime(true);

function executeTask($types){

foreach($types as $type){
case 'updateCache':
echo "updateCache \n";

case 'sentEmail':
echo "sentEmail \n";

case 'logEntry':
echo "logEntry \n";

case 'addDBEntry':
echo "addDBEntry \n";

$useFork = true;

$pid1 = pcntl_fork();
if ($pid1 == -1) {
$types = array("updateCache","sentEmail","logEntry","addDBEntry");
} else if ($pid1) {
$pid2 = pcntl_fork();
if ($pid2 == -1) {
$types = array("updateCache","sentEmail","logEntry");
} else if ($pid2) {
$types = array("updateCache");
} else {
$types = array("sentEmail","logEntry");

} else {
$types = array("addDBEntry");

if($pid1 && $pid2){
$time_end = microtime(true);
$time = $time_end - $time_start;
echo "Total time: $time seconds\n";
} else {
$types = array("updateCache","sentEmail","logEntry","addDBEntry");
$time_end = microtime(true);
$time = $time_end - $time_start;
echo "Total time: $time seconds\n";


Thank you.

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Git branching model

Git branching model :

Following model can be used for feature and fixes.


- Local Server
- Remote Server
- Production Server

- Release branch : “release”
- Development branch : “master”
- Feature branch : “feature”

Local Server:

1)Check current status:

- a)List local branch.

$git branch

- b)List local and remote-tracking branches.

$git branch -a

- c)List local and all remote branches.

$git ls-remote --heads

- d)Check summary of Repository.

$git remote show origin

2)Pull latest updates

$git pull origin master;

3)Create branch: Create branch and make changes.

$git branch feature
$git checkout feature
$git checkout -b feature

Make changes.

4) Add and Commit changes :

$git add file_name
$git commit -m "message"

5)Add new remote branch: Push branch to origin server.

$git push -u origin feature

Development Server:

1)Fetch new branches: Fetch all remote branches.

$git fetch -all

2)Checkout new remote branch: Checkout and track new remote branch.

$git checkout -tb feature origin/feature

Test code.

Local Server:

1)Merge branch: Merge ‘feature’ branch to ‘master’ branch.

$git checkout master;
$git merge feature;

2)Make a feature release.

$git checkout release;
$git pull origin release;
$git merge master;
$git fetch --tags;
$git describe;
$git tag -a -m 'log message'
$git push origin release --tags
$git checkout master;

3)Delete branch: Delete new branch locally and remotely.

$git branch -D feature

$git push origin --delete feature
$git push origin :feature

3)Delete branch: Deletes all stale tracking branches under .
These stale branches have already been removed from the remote repository
referenced by , but are still locally available in “remotes/“.

git remote prune origin

When you use git push origin :feature, it automatically removes origin/feature, so when you ran git remote prune origin, you have pruned some branch that was removed by someone else.
It’s more likely that your co-workers now need to run git prune to get rid of branches you have removed.

Production Server:

1) Fetch and Checkout new tag.

$git fetch --tags
$git checkout

Note:Use “stash” commands to avoid conflicts for uncommitted changes.

$git stash
$git stash pop
$git stash apply

Thanks you.

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Reset mysql root password

Reset mysql root password :

If you set a root password previously, but have forgotten it, you can set a new password. The following sections provide instructions for Unix systems

1) Stop Mysql server.

#sudo /etc/init.d/mysql stop


#sudo kill `sudo cat /var/run/mysqld/`

2) Now lets start up the mysql daemon and skip the grant tables which store the passwords.

#sudo mysqld_safe --skip-grant-tables &

3) Now you should be able to connect to mysql without a password.

#mysql --user=root mysql

4) Update root password.

mysql>update user set Password=PASSWORD('rootnewpassword') where user='rootuser';

mysql>flush privileges;


5) Stop Mysql and Start it again.

#sudo kill `sudo cat /var/run/mysqld/`

#sudo /etc/init.d/mysql start

Thank you.

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Install HP printer driver on Ubuntu

Install HP printer driver on Ubuntu:

Install using repository driver:

# sudo aptitude install hplip

Install using new updated driver:

Follow step on link given below,

HP driver Installation Wizard

if you got following error ,

error: A required dependency 'cups (CUPS - Common Unix Printing System)' is still missing.
error: Installation cannot continue without this dependency.
error: Please manually install this dependency and re-run this installer.

then install ,

# sudo aptitude install hplip

Above command will install dependency from repository.

Again start installation using “HP driver Installation Wizard”.

If you got message regarding “hplip already exist [remove and install | overwrite | quit ]” then say “remove and install”.

It will remove old version from repository and install your new downloaded version.

Start setup in GUI mode whenever asked.

Install HP-plugin from Hp site, if asked.

After completing setup, print test page and you are done.

Happy Printing !!!.

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Shell script multi-processing

Shell script multi processing :

Multi processing using shell script can be achieve by spawning multiple child processes.
There are two method ,

1) Using commands as string :


declare -a NOS=(1 2 3 5 6 7 8);

echo "STR.{}";

for NO in ${NOS[*]}; do echo $NO; done | xargs -P8 -n1 -I{} bash -c "$STR"

2) Exporting commands as function (prefered way) :


fName() { echo "fName.$1"; }

export -f fName

for NO in ${NOS[*]}; do echo $NO; done | xargs -P8 -n1 -I{} bash -c "fName '{}'";

Things to keep in mind,
- You can’t use parent script’s variable in unless you pass them as parameter using xarg.
- You can’t use function from parent script or current shell unless you export it shell console.

3) Using parallel shell tool :
GNU parallel is a shell tool for executing jobs in parallel using one or more computers.
More details can be found here, Parallel Shell Tool

parallel --version

for i in {1..100} ; do
CMD="echo $i > $l";
processTask() { echo "IN => $1"; sleep 2; eval $1 || echo "Error:$LINENO"; }
export -f processTask # Export 'processTask' function to current Shell.
# Process Task parallely using xargs
time for CMD in "${CMD_COMPUTE_REPORT[@]}"; do echo "$CMD"; done | xargs -P$FORK_PROC -n1 -I{} bash -c "processTask '{}'";
# Process Task parallely using parallel
time parallel "processTask {}" ::: "${CMD_COMPUTE_REPORT[@]}"
exit 0;

Thank you.

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Tech Giants Acquisition Strategies

Tech Giants Acquisition Strategies

Compare the acquisition strategies of 5 tech giants over the last 15 years,

Original content produced by simplybusiness.

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