Browsing the internet from the Terminal (command line) in Linux

Browsing the internet from the Terminal (command line) in Linux

There are actually a number of text-mode web-browsers, We are going to see few of them.


Links is a text based web browser written in C language. You may install it from repo.

$ apt-get install links

After installing links you can browse any website within terminal as mentioned below.


To navigate use UP and DOWN arrow keys. RIGHT keys to go links and Left arrow keys to go back to page. Q key for quits.

2. Links2

Links2 is graphical web browser. To install

$ apt-get install links2


to install Lynx

$ apt-get install lynx

To Use

$ lynx

4. w3m

to install

$ apt_get install w3m

to use


That’s all for now. I will be here soon with another interesting topic. Till then stay tuned and connected to Repair Ki Dukan.

We provide doorstep home appliance repair and service.
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Air Conditioner AC Maintenance Guide

Proper air conditioner maintenance or AC system will ensure that the equipment continues to provide the cooling when needed especially during summer. Some of the steps that you can take and do not require a service technician to do them. Equipping yourself with these simple knowledge will save you time and money in the long run.

Check The Condenser
In a typical air conditioner, the condensing unit is usually located outside your house where the compressor, fan and the condensing coils are located. When cooling your house, this unit rejects heat to the surrounding by blowing the fan over the condensing coils. Make sure that there are no obstruction to the fan and air flow of the condenser. A typical outdoor condensing  unit that needs cleaning to ensure efficiency of air conditioner unit.


You do not have to cover up the unit when not in used as these units are robust enough to stand the harsh outside temperature of the house.
Remember to disconnect the power supply to the unit before cleaning the condenser.

Check & Clean Filters
Most indoor evaporator unit is fitted with removeable filters that trapped dust to prevent dirt from clogging the coils of the evaporator. These filters are easily removed and wash with water/soap to get rid of the dust. Do it at least once a month. Some units also come with electrostatic filters that act as a secondary filter system for the evaporator. Change them if they are dirty.

filter ac

Check & Clean Evaporator

If the coils of the indoor evaporator are dirty, use a vacuum cleaner or a wet cloth to clean them. Keeping the evaporator clean will ensure that the cooling capacity of the air conditioner is not lost due to the dirt that obstruct the flow of air to the room.

Remote Control

If your unit has a remote control, make sure that it is working by checking the display and using it to control the unit. If you are not using the controller for a long period, remove the batteries. Learning the functions of the electronic control will ensure that you are able to operate the air conditioner effectively.


Note that there are a few operating modes i.e. cooling, heating, fan or auto mode depending on the system that you purchased. Use of timer and other energy saving modes are recommended to save energy.

Power Up Unit

It is always a good idea to power up the unit and run the air conditioner at the end of Spring to ensure that it is still in working condition. Make sure that you are operating the right mode and temperature to get the desired cooling or heating effect.


Air Conditioner (AC) Ratings

Air Conditioner Ratings

How do you interpret the air conditioner ratings provided by the manufacturers of the equipment that you are comparing? If you are looking for a heat pump or air conditioner unit for your house or office, you may want to do a little bit of homework before going to the shops and purchase the unit.

Getting a suitable equipment that will usually last you for many years is essential as there is a trade off between the initial price and the operating cost over the years.


A good unit that comes with energy saving feature such as inverter control of the compressor is higher cost compared to the normal ON/OFF compressor. This is because the electronic control is very much more complicated and contributes substantially to the cost of the unit. However, the energy efficient unit will save you energy hence your utility bill.

If you add up the savings over the years, you will in fact gain more savings even though your initial investment is higher. Therefore, house owners will usually be willing to pay more for better and efficient unit. Look out for Energy Star or equivalent logo on the equipment.

Air Conditioner Ratings & Typical Specifications

Here are some of the air conditioner ratings you may encounter in the brochures or specifications of the air conditioner or heat pump unit.

1. Capacity

This is the most basic specifications that you should look out for. In ductless split, the range of cooling capacity can go from 9,000 Btu/h to over 30,000 Btu/h. The amount of cooling needed by the space will be used to determine the capacity of the air conditioner needed.

2. COP(Coefficient of Performance)

This coefficient is the ratio of the cooling capacity(W) versus power consumption(W).

COP= Cooling Capacity(W)/Power Consumption(W)

The higher the COP, the higher the efficiency of the air conditioner. Usually the value range from 2-4 but in recent years, the use of inverter compressors have enabled this coefficient to go higher than 4. This formula is also applicable for the heat pump system. See the explanation on heat pump COP.

If the cooling capacity is given in Btu/h, you can convert it to Watt by dividing it with 3.412.

1W= 3.4121 Btu/h

3. EER (Energy Efficiency Ratio)

This rating was established by ARI or Air Conditioning and Refrigeration Institute in 1975 for manufacturers to rate their equipment so that consumers or consultants can tell the cooling efficiency of the air conditioner by just looking at the specifications provided.

This rating is obtained by dividing the cooling capacity(Btu/h) with the input power(Watt). The rating points are at 80 °F dry bulb/67 °F wet bulb indoor temperature and 95 °F dry bulb/75 °F wet bulb outdoor temperatures.

For instance, if you look at the brochure and the unit has a Cooling Capacity = 25,000 Btu/h and Input Power = 2,400 W,

EER = (25,000 Btu/h)/2400W

       = 10.42

The larger the value of EER, the more efficient the air conditioner is. Therefore, choose a bigger EER if you are comparing between two equipment.

The EER has a limitation in that it is measured only when the unit is in steady-state condition. The starting up and shutdown cycles are not included in the calculation.

Therefore, this rating does not give a complete picture of the efficiency of the unit. A better efficiency ratio known as Seasonal Energy Efficiency Ratio or SEER is developed.

Choose wisely these air conditioner ratings as the efficiency of the unit will drop as the unit aged over the years.

The Energy Star Logo

4. SEER (Seasonal Energy Efficiency Ratio)

This ratio is rated by AHRI (Air Conditioning, Heating and Refrigeration Institute) and manufacturers’ equipment ratings are published in their catalogs. This ratio is more accurate as it takes into consideration non steady state conditions such as the start-up and shutdown cycles of the air conditioner.

All central split-cooling system produced in the US must have this ratio effective Jan 23, 2006. In order to ensure more efficient units are produced, a minimum SEER of 13 has been stipulated except for window units which has a minimum SEER of 10.

In choosing the SEER, the choice is always to go for a higher SEER as it is a more efficient equipment. The trade-off in choosing a higher SEER is that usually the initial cost of the equipment will be higher.

This ratio is obtained by dividing the total cooling that the equipment is able to provide over the entire season (Btu) over the total energy in Watt-hours it will consume (Wh).

5. HSPF (Heating Seasonal Performance Factor)

This ratio is used to determine the efficiency of air source heat pumps equipment.

It applies to the heating mode by which the total heating used during the entire season is divided by the energy in Watt-hours that it consumed.

A ratio of greater than 8 is considered an efficient equipment. However, the advancement of better control and inverter compressor have enabled units to have HSPF up to 13.

You will see this figure moving upwards as newer design is being developed.

For example, a ductless split unit heat pump delivering 100,000,000 Btu during the entire season and consuming 12,000 kWh will have a HSPF of:

HSPF = 100,000,000 Btu/12,000 kWh

        = 8.33

The higher the HSPF, the better the unit is.

6. Noise or Sound Level

In ductless split unit, there is an indoor and outdoor unit. The specifications will state the noise level of both the indoor (evaporator) and outdoor (condenser). The lower the dBA value, the quieter it is. Hence, if you are installing a unit in the study room, choose a lower dB level.

The evaporator is always quieter than the condenser unit. Depending on the capacity, the indoor noise level can go down to below 21 dBA and the outdoor unit can go higher than 50 dBA. Higher capacity equipment will have higher sound levels compared to a lower capacity equipment.

7. Refrigerant

The refrigerant used will also determine the pricing of the unit. For example, R22 will be phased out soon whereas R410A is the more ozone friendly refrigerant.

The cost of the newer refrigerant is more costly but you will be helping to reduce the amount of gas that is harmful to the ozone from being used. Ask the dealer on the refrigerant used and get their advice on future replacement and service.

8. Energy Star

Look out for Energy Star rating of the equipment. An equipment with this rating shows that the equipment is designed to save energy hence reducing your electricity bills as well as protecting our environment.

Units that are qualified for Energy Star ratings are listed in the official website. See the Energy Star air conditioner ratings here.



PHP cURL functions

PHP cURL is a function in PHP that makes it possible for PHP programs to use libcurl library.
libcurl is a library created by Daniel Stenberg that allows you to communicate to diffrenet type of servers with many different types of protocols.
libcurl currently supports the http,https,telnet,ftp,gopher,file and ldap protocols.

Using cURL we can do below things:
Retrieving Webpage
Calling Rest API
Sending POST request.
Sending Receiving XML
Uploading File
Passing Custom HTTP header.

PHP cURL uses the following sequence of steps.
curl_init: Initialize a curl session and return a handle which can be used by other cURL functions.
curl_setopt: Set various options for the cURL session handle
curl_exec: Executes a cURL session.
curl_close: Closes the current cURL session and frees all resources. The cURL handle, ch, is also deleted.
Following code returns the curl output as a string.

// create curl resource
$ch = curl_init();

// set url
curl_setopt($ch, CURLOPT_URL, “”);

//return the transfer as a string
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

// $output contains the output string
$output = curl_exec($ch);

// close curl resource to free up system resources


Startup india: 10 firms get tax benefits out of 146

Nirmala Sitharaman, Commerce minister said that only 10 startup firms avail tax benefits out of 146 applications.

As on march 9 government received 1835 application s for seeking recognition as startup india  out of thus only 731 got recognized in which 146 will get tax benefit out if which 10 firms already approved for availing tax benefit.

Install MySQL on Ubuntu

Installation of MySQL

Add MySQL APT Repository

Download MySQL APT repository from

select package for your Linux distribution

Install the downloaded release package with the following command

shell> sudo dpkg -i mysql-apt-config_5.5.7_all.deb

During the installation of the package, you will be asked to choose the versions of the MySQL server and other components (for example, the MySQL Workbench) that you want to install. If you are not sure which version to choose, do not change the default options selected for you.

update package information from the MySQL APT repository with the following command

shell> sudo apt-get update

Install MySQL by the following command:

shell> sudo apt-get install mysql-server

During the installation, there are two requests by the dialogue boxes:Supply a password for the root user for your MySQL installation

Indicate if you want to install the test database with Yes or No. Installation of the test database is not recommended for production environments.

Starting and Stopping the MySQL Server

The MySQL server is started automatically after installation. You can check the status of the MySQL server with the following command:

shell> sudo service mysql status

Stop the MySQL server with the following command:

shell> sudo service mysql stop

To restart the MySQL server, use the following command:

shell> sudo service mysql start


Compiling PHP from source on Linux OS

Step 1:  Download PHP from source

Go to sourcecode and download

cd /home/sourcecode



tar -zxvf php-5.5.38.tar.gz

cd /home/sourcecode/php-5.5.38

Step 2:

Now we have to configure PHP for compilation process. There are hundreds of options which can be provided to configure script. These options include the option to specify where PHP should be installed, which functionality should be enabled, like functionality to access mysql databases from PHP and which extensions have to be compiled etc. To see a list of options supported by PHP configure, type:

$ ./configure –help

It’ll show a list of all options supported by the version of PHP that you are using.

To compile PHP as Apache shared module we have to provide path to apache apxs utility, which in our case was installed in /home/apache2/bin/ when we installed Apache.

$ ./configure –prefix=/home/apach2/php –with-apxs2=/home/apache2/bin/apxs –with-config-file-path=/home/apache2/php –with-mysql

First option –prefix=/home/apach2/php  we want PHP to be installed in /home/apach2/php directory. Otherwise it’ll be installed in some default location (/usr/local).

Second option –with-apxs2 indicates that we want to install PHP as Apache 2 shared module.

Third option –with-config-file-path specifies that PHP should look for php.ini file in /home/apache2/php directory.

Fourth option –with-mysql enables support to access mysql databases through PHP.

step 3:

You have to type make to compile PHP:


Step 4:

make install

if Apache is running stop Apache:

/home/apach2/bin/apachectl stop

Now we need to make some changes in Apache Configuration file in order to handle PHP files.

you need to add the following lines:

LoadModule php5_module modules/

AddType application/x-http-php .php

DirectoryIndex index.php index.html

Save this file and then start Apache:

/home/apach2/bin/apachectl start

Testing the PHP Installation

Now create a PHP file named info.php in /home/apach2/htdocs/



Save info.php and then access it via browser


If you get PHP Configuration. It means you are done. Thumbs Up.


Apache Installation From Source

Compiling and Installing Apache Version 2.4 from source on Linux OS

We create the folder named ‘sourcecode‘ and ‘apache2‘ in /home

mkdir /home/sourcecode

we will use this directory to keep downloaded file

mkdir /home/apache2

at apache2 we are going to Compiling and Installing Apache.

Prerequisite for Apache installation * important

* Apache source code -Download the latest release of Apache from

*  APR and APR-Util Source Code Download Apr from

ANSI-C Compiler and Build System -Make sure you have an ANSI-C compiler installed. The GNU C compiler (GCC) from the Free Software Foundation (FSF) is recommended. If you don’t have GCC then at least make sure your vendor’s compiler is ANSI compliant. In addition, your PATH must contain basic build tools such as make.

Perl-Compatible Regular Expressions Library (PCRE) – Download the source code from or from rpm and package

Step 1: Download

cd /home/sourcecode


extract Apache here

gzip -d httpd-2.4.25 tar.gz

tar xvf httpd-2.4.25.tar

same way extract APR and APR util


gzip -d apr-1.5.2.tar.gz

tar xvf apr-1.5.2.tar

mv apr-1.5.2 /home/sourcecode/httpd-2.4.25/srclib/apr


gzip -d apr-util-1.5.4.tar.gz

tar xvf apr-util-1.5.4.tar.gz

mv apr-util-1.5.4 /home/sourcecode/httpd-2.4.25/srclib/apr-util

Step 2:

cd  /home/sourcecode/httpd-2.4.25

./configure –prefix=/home/apache2 –enable-so

First option –prefix tells configure script that we want Apache to be installed in directory apache2

If we don’t provide a prefix option than it’ll be installed in default location, which is /usr/local/apache2.

Second option –enable-so tells configure to enable module so, which allows Apache to load shared modules.

Step 3: make

Step 4: make install

This will install Apache to /home/apache2

Step 5: Test Apache installation is done by starting Apache

/home/apache2/bin/apachectl start

If you get to shell prompt without any error then Apache is started.

Now you open a browser

http://localhost, which should display the default message “It Works!”

Now your apache is ready

Start Apache automatically during system startup

Modify the /etc/rc.d/init.d/httpd script and change apachectl and httpd variable to point to the appropriate new location



Now, you can perform the following to stop and start the Apache

service httpd stop

service httpd start

Setup the Apache to automatically startup during reboot as shown below.

# chkconfig --list httpd
httpd           0:off   1:off   2:off   3:off   4:off   5:off   6:off
# chkconfig --level 2345 httpd on
# chkconfig --list httpd
httpd           0:off   1:off   2:on    3:on    4:on    5:on    6:off

Apache configure command Line Example

./configure –prefix=/wwwroot –enable-auth-anon –enable-auth-dbm –enable-auth-digest –enable-file-cache –enable-echo –enable-charset-lite –enable-cache –enable-disk-cache –enable-mem-cache –enable-example –enable-ext-filter –enable-case-filter –enable-case-filter-in –enable-deflate –with-z=/usr/local –enable-mime-magic –enable-cern-meta –enable-expires –enable-headers –enable-usertrack –enable-unique-id –enable-proxy –enable-proxy-connect –enable-proxy-ftp –enable-proxy-http –enable-ssl –with-ssl=/usr/local –enable-optional-hook-export –enable-optional-hook-import –enable-optional-fn-import –enable-optional-fn-export –enable-bucketeer –enable-static-support –enable-static-htpasswd –enable-static-htdigest –enable-static-rotatelogs–enable-static-logresolve –enable-static-htdbm –enable-static-ab –enable-static-checkgid –enable-http –enable-dav –enable-info –enable-cgi –enable-cgid –enable-dav-fs –enable-vhost-alias –enable-rewrite –enable-so