Installing Ruby using RVM

RVM (Ruby Version Manager) - program that lets you use several versions of Ruby on one VPS. In this we will use ruby 2.0.0p247

Step 1: Install RVM

Update the system.

sudo yum update

make sure you have curl on the system

sudo yum install curl

To install RVM

curl -L get.rvm.io | bash -s stable

After it is done installing, load RVM. To install RVM

source /etc/profile.d/rvm.sh

To check all the dependencies of the RVM. Install the results using rvmsudo.

rvm requirements

Additional Dependencies:
# For Ruby / Ruby HEAD (MRI, Rubinius, & REE), install the following:
  ruby: yum install -y gcc-c++ patch readline readline-devel zlib zlib-devel libyaml-devel libffi-devel openssl-devel make bzip2 autoconf automake libtool bison iconv-devel ## NOTE: For centos >= 5.4 iconv-devel is provided by glibc

rvmsudo yum install -y gcc-c++ patch readline readline-devel zlib zlib-devel libyaml-devel libffi-devel openssl-devel make bzip2 autoconf automake libtool bison iconv-devel

Step 2: Install Ruby

I want to use ruby 2.0.0p247 and I will download in via rvm remote installation. You can skip the two command below and proceed to the next on but If you need some information or you want to another version of ruby you can check the rvm help and list

rvm help install

rvm list known

To get ruby 2.0.0p247 fron remote

rvm list remote

To download and install: rvm install {name} --binary

rvm install ruby-2.0.0-p247 --binary

Check the your ruby version and the location.

ruby -v

ruby 2.0.0p247 (2013-06-27 revision 41674) [x86_64-linux]

which ruby

/usr/local/rvm/rubies/ruby-2.0.0-p247/bin/ruby

reference: https://www.digitalocean.com/community/articles/how-to-install-ruby-on-rails-on-centos-6-with-rvm

Installing Ruby on Rail on Centos 6 (64 bit) Virtual Machine

Ruby on Rails

Prerequisites

Ruby language version 1.9.3 or newer

The RubyGems packaging system

A working installation of the SQLite3 Database

On my development environment, I used centos 6 64 bit minimal (no GUI) operating system to run ruby on rails. I installed it on Oracle Virtualbox.

Step 1: Install the Ruby
Check the ruby version.

[root@centosAshley02 ~]# ruby -v
-bash: ruby: command not found

No found command means we have to intall ruby.
Install the wget command to download source files

[root@centosAshley02 ~]# yum install wget

Download rpm and update the system

[root@centosAshley02 ~]# cd /tmp/
[root@centosAshley02 ~]# wget http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
[root@centosAshley02 ~]# rpm -Uvh epel-release-6-8.noarch.rpm
[root@centosAshley02 ~]# yum -y update

[root@centosAshley02 ~]# yum -y groupinstall "Development Tools"
[root@centosAshley02 ~]# yum -y install libxslt-devel libyaml-devel libxml2-devel gdbm-devel libffi-devel zlib-devel openssl-devel libyaml-devel readline-devel curl-devel openssl-devel pcre-devel git memcached-devel valgrind-devel mysql-devel ImageMagick-devel ImageMagick
 

Get the latest ruby version using wget command

[root@centosAshley02 ~]# cd /usr/src/
[root@centosAshley02 ~]# wget ftp://ftp.ruby-lang.org/pub/ruby/2.0/ruby-2.0.0-p353.tar.gz
[root@centosAshley02 ~]# tar zxvf ruby-2.0.0-p353.tar.gz
[root@centosAshley02 ~]# cd ruby-2.0.0-p353
[root@centosAshley02 ~]# ./configure
[root@centosAshley02 ~]# make
[root@centosAshley02 ~]# make install

Show the ruby version.

[root@centosAshley02 ~]# ruby -v
ruby 2.0.0p353 (2013-11-22 revision 43784) [x86_64-linux]

Step 2: Install the Rubygems

[root@centosAshley02 ~]# cd /usr/src/
[root@centosAshley02 src]# wget http://production.cf.rubygems.org/rubygems/rubygems-2.1.7.tgz
[root@centosAshley02 src]# tar zxvf rubygems-2.1.7.tgz
[root@centosAshley02 src]# cd rubygems-2.1.7
[root@centosAshley02 rubygems-2.1.7]# /usr/local/bin/ruby setup.rb

Check the rubygem installation, the back to parent directory

[root@centosAshley02 rubygems-2.1.7]# gem -v
2.1.7
[root@centosAshley02 rubygems-2.1.7]# cd

Step:3 Install Sqlite
If you don't have curl then execute the following

[root@centosAshley02 ~]# yum install curl

Install rvm

curl -L get.rvm.io | bash -s stable

Source the file rvm.sh

source /etc/profile.d/rvm.sh

for me to check, I type.

[root@centosAshley02 ~]# rvm requirements
Checking requirements for centos.
Requirements installation successful.

Step 4: Sqlite

[root@centosAshley02 ~]# cd /opt/
[root@centosAshley02 opt]# wget http://www.sqlite.org/2013/sqlite-autoconf-3080100.tar.gz
[root@centosAshley02 opt]# tar xvzf sqlite-autoconf-3080100.tar.gz
[root@centosAshley02 opt]# ln -s /opt/sqlite-autoconf-3080100/ /opt/sqlite3
[root@centosAshley02 opt]# cd sqlite3/
[root@centosAshley02 opt]# ./configure --prefix=/opt/sqlite3

Configure the .bashrc

[root@centosAshley02 ~]# vi .bashrc

add on the .bashrc LD_LIBRARY_PATH=/usr/local/lib64 then source and test the varibale

[root@centosAshley02 ~]# source .bashrc
[root@centosAshley02 ~]# echo $LD_LIBRARY_PATH
/usr/local/lib64
[root@centosAshley02 ~]# export LD_LIBRARY_PATH=/usr/local/lib64:$LD_LIBRARY_PATH

Then make and make install

[root@centosAshley02 ~]# cd /opt/sqlite3
[root@centosAshley02 sqlite3]# make
[root@centosAshley02 sqlite3]# make install

Test the sqlite,

[root@centosAshley02 ~]# mkdir -p /usr/local/sqlite/var
[root@centosAshley02 ~]# sqlite3 /usr/local/sqlite/var/testdb
SQLite version 3.6.20
Enter ".help" for instructions
Enter SQL statements terminated with a ";"
sqlite>

Then .exit, for more info type .help
Step 5: Install the rails
This may take time. Please be patient.

[root@centosAshley02 ~]# gem install rails

Check the gems installed.

[root@centosAshley02 ~]# gem list

*** LOCAL GEMS ***

actionmailer (4.0.1)
actionpack (4.0.1)
activemodel (4.0.1)
activerecord (4.0.1)
activerecord-deprecated_finders (1.0.3)
activesupport (4.0.1)
arel (4.0.1)
atomic (1.1.14)
bigdecimal (1.2.0)
builder (3.1.4)
bundler (1.3.5)
erubis (2.7.0)
hike (1.2.3)
i18n (0.6.5)
io-console (0.4.2)
json (1.7.7)
mail (2.5.4)
mime-types (1.25.1)
minitest (4.3.2)
multi_json (1.8.2)
polyglot (0.3.3)
psych (2.0.0)
rack (1.5.2)
rack-test (0.6.2)
rails (4.0.1)
railties (4.0.1)
rake (0.9.6)
rdoc (4.0.0)
sprockets (2.10.1)
sprockets-rails (2.0.1)
test-unit (2.0.0.0)
thor (0.18.1)
thread_safe (0.1.3)
tilt (1.4.1)
treetop (1.4.15)
tzinfo (0.3.38)

Install the sqlite-ruby

[root@centosAshley02 ~]# yum install sqlite-devel
[root@centosAshley02 ~]# gem install sqlite3

check the gem list again and find the sqlite

[root@centosAshley02 ~]# gem list

*** LOCAL GEMS ***

actionmailer (4.0.1)
actionpack (4.0.1)
activemodel (4.0.1)
activerecord (4.0.1)
activerecord-deprecated_finders (1.0.3)
activesupport (4.0.1)
arel (4.0.1)
atomic (1.1.14)
bigdecimal (1.2.0)
builder (3.1.4)
bundler (1.3.5)
erubis (2.7.0)
hike (1.2.3)
i18n (0.6.5)
io-console (0.4.2)
json (1.7.7)
mail (2.5.4)
mime-types (1.25.1)
minitest (4.3.2)
multi_json (1.8.2)
polyglot (0.3.3)
psych (2.0.0)
rack (1.5.2)
rack-test (0.6.2)
rails (4.0.1)
railties (4.0.1)
rake (0.9.6)
rdoc (4.0.0)
sprockets (2.10.1)
sprockets-rails (2.0.1)
sqlite3 (1.3.8)
sqlite3-ruby (1.3.3)
test-unit (2.0.0.0)
thor (0.18.1)
thread_safe (0.1.3)
tilt (1.4.1)
treetop (1.4.15)
tzinfo (0.3.38)

Almost done, We have to install execjs for javascript runtime and rubyracer

gem install debugger-ruby_core_source -v 1.2.2

sources: http://guides.rubyonrails.org/getting_started.html
https://gist.github.com/fabrizioc1/1083087
http://sqlrelay.sourceforge.net/sqlrelay/gettingstarted/sqlite.html https://github.com/cldwalker/debugger/issues/12

Palindrome in Ruby

A palindrome is a word, phrase, number, or other sequence of symbols or elements, whose meaning may be interpreted the same way in either forward or reverse direction. Examples: "Amore, Roma.", "A man, a plan, a canal: Panama." or "No “x” in “Nixon.”"

The palindrome code in ruby is very short also similar to other OOP languages. Check my code below.

#!/usr/bin/env ruby

print "Enter string: "

str = gets

strnew = str.downcase.scan(/\w/)

if strnew == strnew.reverse

        puts strnew.to_s << " is a palindrome"

end