I am currently working on a new Rails project. Its been a while since I worked with rails – so I updated Rails using the command ‘sudo gem update --system‘. I started the inbuilt server and tried to open a page – and to my surprise, I found that Rails is having trouble connecting to the MySQL server. It was apparent that the mysql gem was missing. So I tried to install it using the command ‘sudo gem install mysql‘. That failed too – this is the error I got…

Building native extensions.  This could take a while...
ERROR:  Error installing mysql:
        ERROR: Failed to build gem native extension.

/usr/bin/ruby extconf.rb install mysql
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lm... yes
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lz... yes
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lsocket... no
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lnsl... yes
checking for mysql_query() in -lmysqlclient... no
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers.  Check the mkmf.log file for more
details.  You may need configuration options.

Provided configuration options:
        --with-opt-dir
        --without-opt-dir
        --with-opt-include
        --without-opt-include=${opt-dir}/include
        --with-opt-lib
        --without-opt-lib=${opt-dir}/lib
        --with-make-prog
        --without-make-prog
        --srcdir=.
        --curdir
        --ruby=/usr/bin/ruby
        --with-mysql-config
        --without-mysql-config
        --with-mysql-dir
        --without-mysql-dir
        --with-mysql-include
        --without-mysql-include=${mysql-dir}/include
        --with-mysql-lib
        --without-mysql-lib=${mysql-dir}/lib
        --with-mysqlclientlib
        --without-mysqlclientlib
        --with-mlib
        --without-mlib
        --with-mysqlclientlib
        --without-mysqlclientlib
        --with-zlib
        --without-zlib
        --with-mysqlclientlib
        --without-mysqlclientlib
        --with-socketlib
        --without-socketlib
        --with-mysqlclientlib
        --without-mysqlclientlib
        --with-nsllib
        --without-nsllib
        --with-mysqlclientlib
        --without-mysqlclientlib

Gem files will remain installed in /usr/lib/ruby/gems/1.8/gems/mysql-2.7 for inspection.
Results logged to /usr/lib/ruby/gems/1.8/gems/mysql-2.7/gem_make.out

After a couple of hours on Google, I managed to fix the issue – and I am posting the solution here for others who might run into the same problem.

Install the necessary Libraries

First, you must install a couple of mysql libraries(I am assuming that you have MySQL server already installed). If you are on Red Hat/Fedora/CentOS etc., run the command…

sudo yum install ruby-mysql mysql-devel

If you are on Debian/Ubuntu/etc., run this command…

sudo apt-get install libmysqlclient15-dev libmysqlclient15off libmysql-ruby

Install the gem

Once the installation is done, enter this command to install mysql gem…

sudo gem install mysql -- --with-mysql-config=/usr/bin/mysql_config

If your mysql_config is not in the standard location, update the command with the right path.

The mysql gem should be installed now. These commands worked for me – your milage may vary. If you still have trouble, try one of the following links…

More Resources

• Connecting To MySQL using Ruby
• MySQL => Rails Wiki

If you are a Windows user who want more stability(but unwilling to switch to Linux completely), this post is for you. Basically, you have to create a dual boot system with Linux and Windows – and use Linux for doing the more ‘unsafe’ operations. The end result is windows remains stable – and you will be able to do things that are potentially dangerous.

Dual Boot System

Install a Linux distro on your system. I would recommend Ubuntu if you are a beginner and Fedora if you are not. There are many tutorials on the net that will take you through the process of installing – so I am not going into it. Now boot into Linux when ever you wish to do stuff that might run the risk of infecting your system…

Browsing

Unfortunately, the net is currently the number one source of virus infection. So, if you want to browse, boot into linux and browse – this will make it impossible for virus to infect the system. But there are some problems with this approach…

• Might be impractical for full time broadband users
• Some special applications might not have linux alternatives(eg. Online games, Yahoo Video Chat software etc.
• Some ISP’s dialup applications might not work on Linux

My brother uses this method – and he swears by it. It will cut down virus infections by about 75%.

Using Pen Drives/External Hard Drives

Another method that virus use to propagate itself is pen drives. Everytime you connect a pen drive to your system, you run the risk of getting a virus infection. Using linux to check out pen drives will make sure you will not get infected this way. Its so effective that my brother prefers to check the pen drive in linux over checking it with a anti-virus.

Troubleshooting Help

Another advantage of having Linux in your system is that you can use it to troubleshoot hardware. Say that you mouse stops working – now you have to decide if its a hardware or a software issue. It could be a symptom of a virus – or it could be a problem with the mouse. If you just have windows, the only way to find out is to connect a different mouse – not the most convenient way. But if you have linux, just boot into it. If the mouse is working in Linux, its a software issue. If not, then the hardware is to blame.

Emergency Computing

When disaster strikes(in case of windows, once every six months) and your windows system is rendered unbootable, you have a bailout mechanism. You can use Linux to work on that urgent presentation, or backup the files, or send that email, etc. Point is, you have a working system – until you re-install Windows – or choose to abandon it for Linux.

Linux Live CD/DVD

If you don’t want to install linux due to some(propably invalid) reason, then your next best bet is to have a Linux Live CD handy. Live CDs enable you to have a complete OS that boots directly from the CD/DVD. I would recommend Knopix for this. Just make sure that it works on your system – and you are able to mount your partitions and do read/write operations using the Live CD.

You can use the live CD to troubleshoot hardware and to backup the files in case your ‘Window is broken’. It might not be practical for the other reasons outlined above – because its slower than a permanent solution.

Ironically, we have reached a point that, if you want a stable Windows system, you need to have Linux installed.

After two articles on installing Apache, lets take a look at installing and configuring lighttpd web server on a linux system. lighttpd (pronounced “lighty”) is a web server designed to be secure, fast, standards-compliant and flexible while having a low memory footprint.

Before installation, a few points to remember. These instruction are not for a production environment – this is for a development environment. To install the software, you need root access. You can get that using this command…

su -
[Enter root password]

or by prefixing ‘sudo‘ before each command.

Installing the Server

First install lighttpd and PHP – use your distro’s package management(yum, apt-get) system to do this.

Install lighttpd

You can use this command in Red Hat based systems(Fedora, Cent OS, etc.) to install lighttpd. Debian/Ubuntu systems might the same package name – could someone post the package name of lighttpd in the comments?

yum install lighttpd lighttpd-fastcgi

Install PHP

If you don’t have PHP, you can install it using the command…

yum install php php-cli php-common

In Debian/Ubuntu systems, the command is…

apt-get install php5-cli php5-common php5-cgi

You can make sure you have php-cgi(needed for working with lighttpd) by running this command…

php-cgi -v

Installing MySQL

If MySQL is not yet installed, use this command to install it…

yum install mysql-server php-mysql mysql mysql-libs

Debian/Ubuntu Command…

apt-get install mysql-client mysql-common mysql-server php5-mysql

Configuring lighttpd

lighttpd configuration is done by editing the text file ‘/etc/lighttpd/lighttpd.conf’.

Enable some lighttpd modules by removing the comment character(#) from the beginning of the line. I have enabled the following modules…

server.modules              = (
                                "mod_rewrite",
                                "mod_redirect",
                                "mod_access",
                                "mod_fastcgi",
                                "mod_accesslog" )

Configure lighttpd’s document root – if you already have Apache, I would recommend using the same document root as Apache(applicable for development servers only).

server.document-root        = "/var/www/"

I find it helpful to enable folder listing in my server.

## virtual directory listings
dir-listing.activate       = "enable"

Turn On FastCGI PHP Support

Now, make sure lighttpd works with PHP – first get the path of php-cgi using the command..

$ whereis php-cgi
php-cgi: /usr/bin/php-cgi #Might be different on your system.

Then add the path to the configuration file of lighttpd…

#### fastcgi module
## read fastcgi.txt for more info
## for PHP don't forget to set cgi.fix_pathinfo = 1 in the php.ini
fastcgi.server             = ( ".php" =>
                               ( "localhost" =>
                                 (
                                   "socket" => "/tmp/php.socket",
                                   "bin-path" => "/usr/bin/php-cgi"
                                 )
                               )
                            )

Make sure you uncomment the above lines by removing the ‘#’ characters.

After you are done, save the file. Time to try out the server.

Starting the lighttpd Server

First stop Apache if it is running…

/etc/init.d/httpd stop

Now start lighttpd using the command

/etc/init.d/lighttpd start

Go to your document root(/var/www) and create a php files called ‘info.php’ and put this code inside it…

<?php
phpInfo();

Now fire up a browser and go to localhost – you should see a file listing page with a ‘info.php’ in the list. Click on that link – if you see a PHP information page, your web server is setup correctly.

To make sure MySQL-PHP connection is working, install phpMyAdmin – or write a database connection script – whatever is easier for you.

Related Links

• lighttpd fly light
• lighttpd – Wikipedia
• Lighttpd install perl, mysql support in chrooted jail
• Lighttpd PHP fastcgi configuration
• FreeBSD Install Lighttpd Web Server
• Install lighttpd with php
• Install and Configure lighttpd
• Installing Lighttpd With PHP5 And MySQL Support On Fedora 7

Shameless Plug: If you are a Linux user, you may want to check out my Linux Blog – LinDesk – its about Linux on the Desktop – Articles, Application Reviews and Tutorials about many aspects of Linux included configuration and scripting.

Installing the LAMP environment on a Linux system is easy if you are comfortable with using the native package management software. If you on a Red Hat/Fedora/CentOS system, that will be yum – and for Debian/Ubuntu systems, that will be apt. This tutorial shows you how to install Apache 2, PHP 5 and MySQL 5 in Debian using apt.

Before installation, a few points to remember. These instruction are not for a production environment – this is for a development environment. To install the software, you need root access. You can get that using this command…

su -
[Enter root password]

Installing Apache 2

Use this command to install Apache 2.

apt-get install apache2

Make sure you specify ‘apache2′ – or else, apache 1.3 will be installed.

Install PHP 5

Now, install the PHP 5 packages…

apt-get install libapache2-mod-php5 php5-cli php5-common php5-cgi

No go to the folder /etc/apache2/sites-enabled/ and edit the file in that directory(usually 000-default). Find the line that says
RedirectMatch ^/$ /apache2-default/
and remove it.

Now your document root is /var/www/ – place all your HTML documents and scripts in this folder. If you want to make some other configuration changes, edit the configuration files at /etc/apache2/apache2.conf

I also had to make the following changes…

• Changed the owner of /var/log/apache2 to www-data – I used the command chown www-data:www-data apache2
• Created an empty file at /etc/apache2/httpd.conf

This was to fix a few errors I saw on my system – you may not have to do it.

Install MySQL

This is the command to install MySQL server, its client and PHP’s MySQL libraries…

apt-get install mysql-client mysql-common mysql-server php5-mysql

Finally, Install the other packages you need as well

apt-get install php5-sqlite php5-gd ...

Testing the System

Go to your document root(/var/www) and create a php files called ‘info.php’ and put this code inside that…

<?php
phpinfo();

Start the Servers

First, turn on the MySQL database server…

/etc/init.d/mysql start

Then, start the Apache Web Server…

/etc/init.d/apache2 start

Now fire up a browser and go to localhost – you should see a file listing page with a ‘info.php’ in the list. Click on that link – if you see a PHP information page, your web server is setup correctly.

To make sure MySQL-PHP connection is working, install phpMyAdmin – or write a database connection script – whatever is easier for you.

Related Links

• How To Install Or Upgrade LAMP: Linux, Apache, MySQL and PHP Stack Using Yum
• Apache2 installation and configuration with php support
• Install and Configure Apache2 with PHP5 and SSL Support in Debian Etch
• Setting Up Your PHP Server Environment Using Linux, Apache, MySQL, and PHP
• Quick Linux Server w/ Apache+PHP+MySQL
• LAMP (Linux Apache Mysql PHP) Configuration and Installing in Debian
• HOWTO: Installing MySQL and Apache with PHP support on Linux
• How to install Apache2, PHP5, MySQL5 on RedHat

Shameless Plug: If you are a Linux user, you may want to check out my Linux Blog – LinDesk – its about Linux on the Desktop – Articles, Application Reviews and Tutorials about many aspects of Linux included configuration and scripting.

bash

bash is the most commonly used shell in Linux. That makes the bash scripting language the most popular shell scripting language. OK, maybe after batch. But then again, bash is much more powerful than batch(DOS scripting language). If want to learn bash, I will recommend this tutorial – Advanced Bash Scripting

Officially, I hate bash. I use perl or other similar high level language to create shell script. I use bash only for the simplest scripts. But even I admit that bash has its uses. So, here is the hello script for bash…

Hello Script

#!/usr/sh

# Printing(IO)
echo "Hello World"

# Variables, concatenation
name='Binny'
year=2008
echo "Hello, " $name " - welcome to " $year

#If,else conditions
if [ $year -gt 2008 ]; then
	echo "Welcome to the future - yes, we have flying cars!"

elif [ $year -lt 2008 ]; then
	echo "The past - please don't change anything. Don't step on any butterflies. And for the sake of all that's good and holy, stay away from your parents!"

else
	echo "Anything wrong with your time machine? You have not gone anywhere, kiddo."
fi

# If you are using anything after this, consider using a high level language.
# For loop
for i in 1 2 3
do
	echo $i ") Hi there!"
done

#Numerical Array, foreach
rules[0]="Do no harm"
rules[1]="Obey"
rules[2]="Continue Living"

for ((i=0; i < 3; i++))
do
	echo "Rule" `expr $i + 1` ":" ${rules[$i]}
done

#A While Demo
keys=(hello foo lorem)

i=0
while [ $i -lt 3 ]
do
	echo ${keys[$i]}
	i=`expr $i + 1`
done

# Function, argument, return, call
hello () {
	myname=$1  #First argument.
	echo "Hello" $myname
}
hello "Binny"

# File IO
# File reading
contents=`cat Hello.sh` #For some reason, I'm losing all the \n's in the file.
echo "Hello has `echo $contents|wc -m` chars" # Or wc -m Hello.sh

# Writing to a file
echo "Hello World from shell script" > /tmp/hello.txt

# Command Executing
ls

# Regular Expressions
string="Hello World"
evil=`echo $string | grep '^Hell'`
if [ "$evil" != "" ]; then
	echo "Yup - its evil"
fi
echo "Hello World" | sed -e 's/l//g' #Will return Heo Word

# http://tldp.org/LDP/abs/html/

And, by the way, this will work only in Linux – or if you installed cygwin in your Windows system. Use sh <File_Name> to execute the above code.

Are URLs Case Sensitive?

They should not be – but they sometimes are. Domain names are not case sensitive – for example http://www.apache.org/ and http://WWW.Apache.Org/ goes to the same location. But in the LAMP platform, the path is case sensitive…

• http://www.apache.org/foundation/getinvolved.html is not
• http://www.apache.org/Foundation/GetInvolved.HTML

But in the case of Microsoft IIS server, this is not true – try…

• http://www.microsoft.com/WindowsServer2003/IIS/Default.mspx is the same as
• http://www.microsoft.com/windowsserver2003/iis/default.mspx

Reason: Linux Filesystem is Case Sensitive

The root cause of this is that the filesystem in the Linux OS is case sensitive – while FAT32/NTFS filesystems in Windows are not.

Dynamic URLs

Now Dynamic/friendly/clean URLs are appearing in many CMS tools. A good example for this is the ‘permalink structure’ in WordPress. These dynamic URLs could be case sensitive or not – it depends on the software. In WordPress they are case insensitive. Del.icio.us is also case insensitive. TinyURL is another service that uses case insensitive URLs. But it is possible for the tool to make the URLs case sensitive.

From the SEO perspective

If the search bot visits two urls say, example.com/MyWebPage/Index and example.com/mywebpage/index , will the bot index both page contents? If they are same, will one get the duplicate content penalty? Or will google just index the URL with lower case and ignore the other – remember, in Linux/Apache, both pages may have different content.

Conclusion

The RFC for URL says they must be case insensitive.

For resiliency, programs interpreting URLs should treat upper case letters as equivalent to lower case in scheme names (e.g., allow “HTTP” as well as “http”).

Apache must not use the filesystem as an excuse – I really hope they provide case insensitive URLs

I have a new blog – LinDesk. LinDesk concentrates on the use of Linux on the Desktop. I am trying to keep it distro agnostic – but there is a slight leaning towards Fedora – as it is the distro I am using. Also, you might find a disproportionate amount of articles about KDE.

Actually this blog has been around for some time. The first article appeared on April 8. But I did not announce it so that there can be a build up of articles before it goes public.

Take a look at LinDesk – and if you are a fan of the Linux operating system, subscribe.

Some Popular Posts

• Konqueror – A Killer App for Linux
• Konqueror, The Browser
• Using Konqueror as an FTP Client
• Internet Connection Sharing using iptables
• How to Mount ISO/MDF Images in Linux
• Top 5 Video Players in Linux
• Wesnoth – The Battle for Productivity

So what do you guys think of the new blog? Is it a good move? Or am I moving towards an early burnout?