Installing RVM System Wide

Today I got introduced to one very nice solution developed by Wayne E. Seguin. It is called RVM and it is recommended for ruby developers working on Debian machines.

What is RVM ?

Simply RVM allows users to install multiple ruby versions and switch between them easily. It also allows having multiple sets of gems for different projects easily.

Installation Steps

Before getting into details, I would like to say that any steps mentioned here are grabbed from these two links. I only collected parts from them and added them in an easy way

http://rvm.beginrescueend.com/rvm/install/
http://rvm.beginrescueend.com/deployment/system-wide/
http://rvm.beginrescueend.com/rubies/installing/

1. from your linux console run
2. bash < <( curl -L http://bit.ly/rvm-install-system-wide )
3. you now have rvm command installed here at /usr/local/lib/rvm
4. After installation you should add this line below to your profile
5. [[ -s "/usr/local/lib/rvm" ]] && . "/usr/local/lib/rvm"
6. To do so, i added the line above at the end of the /etc/profile file. But, you can add it in other places according to your needs. Read more about profiles here
7. then run this one
8. source /usr/local/lib/rvm

Now you are ready to install any versions of Ruby and Ruby Enterprise versions available

For me, I installed Ruby 1.8.7 and its enterprise version this way

1. rvm install 1.8.7
2. rvm install ree-1.8.7

That’s it
Hope you enjoy RVM as I hope I enjoy it as well

Forget root password of a Debian Machine & resetting it

I am writing this small post just because

• i forgot the root password of my debian machine
• didn’t find a through post that list all steps in one place and had to look at several ones at a time

The steps are as follows

I am quoting these lines from that post

Some Linux distribution, such as Ubuntu for instance, offer a specific boot menu entry where it is stated "Recovery Mode" or "Single-User Mode". If this is your case, selecting this menu entry will boot your machine into single user mode, you can carry on with the next part. If not, you might want to read this part.

Using GRUB, you can manually edit the proposed menu entry at boot time. To do so, when GRUB is presenting the menu list (you might need to press ESC first), follow those instructions:

• use the arrows to select the boot entry you want to modify.
• press e to edit the entry
• use the arrows to go to kernel line
• press e to edit this entry
• at the end of the line add the word single
• press ESC to go back to the parent menu
• press b to boot this kernel

The kernel should be booting as usual (except for the graphical splash screen you might be used to), and you will finally get a root prompt (sh#).

Here we are, we have gained root access to the filesystem, let's finally change the password.

According to the above words, we should be ok and we have access to the file system. At this state you run the command “passwd” and enter the new password.

If it worked with you then Thanks to the editor. If you got some problems like me, then keep reading.

Problem 1

After editing grub line and add the “single” keyword at the end of that line. I got it loading well until i was prompted for the root password for maintenance and give the ability to skip but by then i will be leaving runlevel 1 and entering runlevel 2 getting login/password prompt i am trying to skip.

To solve this problem do the following:

• Edit the grub line again and leave the keyword “single” there as before but add at the end as well these words “init=/bin/bash”
• exit edit mode
• press the button “b” while you have this modified grub line highlighted to start booting with this modified grub line

Voila, you have now access to shell as a root. run the command “passwd” and you should be fine entering the new desired password. If you got a problem, then continue reading.

Problem 2

Whenever i run the command “passwd” and re-enter the new password i get this error at the end

authentication token lock busy

If so, know that the problem is that you are accessing the system in read-only mode. In order to access it in read-write mode, do the following.

From the shell run this command

mount -o remount,rw /

after that run “passwd” command and this time you should have the ability to enter the new password

and live happily ever after

Install Mechanize On Debian

Installing mechanize gem on Debian should be as easy as running this command

gem install mechanize

but this won’t succeed unless you install these packages on your Debian machine

apt-get install libxml-dev libxslt1-dev

Once installed, gem will be installed seamlessly

Update:

if the above apt-get command didn't work with you and you got an error that package doesn't exist

try this new line

apt-get install libxml2-dev libxslt1-dev

as some packages names has changed

Giants Alliance

Two giants are there one called Windows and another called Linux. As i am fan of Windows Interfaces and Usability (by the way i use Windows XP) and also fan of the extreme shell power of Linux, I wished if i can exploit these two powers at the same time.

The solution i found was using Windows XP as my primary OS and adding Debian version on virtual machine. You may be asking why should this solution be said when it is well known and made by some many users but actually, i made some modifications to this solution.

What i did can be summarized in these following points:

• installing debian without any interface at all, just a shell no more
• using virtual machine shared folder technique to share a folder between my XP machine and my Linux machine
• installed ZOC program which is a powerful shell program that allows connecting using openssh and supports multi tabs which is very important feature not available in putty
• installed openssh-server on debian
• fixed an IP for my debian machine so as to save my openssh configuration one time only without changing it each time i connect to it

This way, i enjoy my XP machine and whenever i need the shell of linux. i connect using openssh on my debian virtualized machine and do what i want

I use this solution while developing ROR applications, i prepared the environment i use as follows

• installed ruby, rails, mysql on my debian machine
• opened remote connections to mysql database so as to use MySQL Query Browser from XP machine

Now, i open my IDE on XP machine that changes in folders place in the shared folder between two machines and i open my server from virtual machine and test apps on debian machine IP rather than my localhost

This experience is great and i enjoy it so much as i feel i have the power of each environment Windows & Linux at the same time

In order to optimize the performance of my Virtual Machine somehow, i raised the priority of these virtualized processes to ‘High’ or even ‘Realtime’. it is now better but not perfect

I think in order to raise the performance significantly, i need to buy another motherboard supporting Intel VT technology. Using such technology i can move virtualization from software layer (being a process that Windows XP Scheduler deal with) to hardware layer which should improve performance as stated

That’s it, i suggest you try this experience and Enjoy as i do